1.5/1.6 DVVT Engine
Maintenance Manual
2018WXSC-4GB-001-1
March 2018
Engine Company After-Sales Service Department
Countersign
Approve
Checking
Proofread
Compile
Engine Maintenance Manual
Preface
To help JAC engine authorized professional maintenance technicians for an effective and proper
maintenance and repair of the JAC refine 1.5/1.6 DVVT engines, this special engine maintenance
manual is prepared.
In order to ensure customer satisfaction of JAC engine products, it is absolutely necessary for the
service technician of JAC engine to have a friendly and correct operation. Therefore, the maintenance
technicians must fully understand the contents of this manual. This manual shall be accessible for
reference at any time.
All contents in this manual, including pictures, technical parameters are the latest. Due to the
product updates, JAC engine company will provide technical briefs or supplemental volumes, so please
pay close attention to the latest developments in obtaining relevant information. JAC engine company
reserves the right to make changes in product design, additions or improvements.
This manual may not be reproduced or modified in any form, including but not limited to electronic,
paper, audio-visual and mechanical, without the written authorization of JAC Engine Company.
The final interpretation of this manual belongs to the Customer Service Department of JAC Engine
Company.
In the process of maintenance and repair of JAC engine product, the use of non-JAC engine
parts or unqualified fuel, may cause damage to the engine.
JAC Engine Company, Anhui Janghuai Automobile Co., Ltd.
March 2018
Engine Maintenance Manual
Content
Preface........................................................................................................................................................... 1
Content...........................................................................................................................................................2
Abbreviation definition..................................................................................................................................1
Chapter 1 Engine Machinery...................................................................................................................... 2
1.1 Engine main technical specifications and parameters..................................................................... 2
1.1.1 Main technical specifications................................................................................................2
1.1.2 Main parts specifications...................................................................................................... 3
1.1.3 Main inspection and adjustment parameters.........................................................................3
1.1.4 Bolt torque table....................................................................................................................3
1.1.4 Maintenance limitation......................................................................................................... 7
1.2 Engine body..................................................................................................................................... 9
1.2.1 Common precautions............................................................................................................ 9
1.2.2 Precautions for sealant........................................................................................................ 10
1.2.3 Preparation work.................................................................................................................11
1.2.4 Engine belt.......................................................................................................................... 15
1.2.5 Air inlet manifold and exhaust manifold............................................................................ 16
1.2.6 Timing sprocket mechanism...............................................................................................18
1.2. Camshaft Assembly.............................................................................................................. 21
1.2.8 Cylinder head......................................................................................................................26
1.2.9 Valve...................................................................................................................................30
1.2.10 Cylinder block assembly...................................................................................................32
1.3 Engine lubricating system..............................................................................................................49
1.3
、
Installation precautions....................................................................................................... 49
1.3.2 Engine oil............................................................................................................................50
1.3.3 Engine Oil Filter................................................................................................................. 52
1.3.4 Oil pan and Oil pump..........................................................................................................53
1.4 Engine cooling system................................................................................................................... 56
1.4.1 Cooling circuit.................................................................................................................... 56
1.4.2 Engine Coolant................................................................................................................... 56
1.4.3 Water pump.........................................................................................................................59
1.4.4 Thermostat assy.................................................................................................................. 60
1.4.5 Water pipe assy...................................................................................................................61
1.5 Engine emission control system.................................................................................................... 63
1.5.1 Fuel evaporation system..................................................................................................... 63
1.5.2 Crankshaft box force ventilation system............................................................................ 66
Chapter 2 Engine Electric Appliance........................................................................................................69
2.1 Ignition system...............................................................................................................................69
2.1.1 Ignition coil.........................................................................................................................69
2.1.2 common fault diagnosis...................................................................................................... 70
2.1.3 Maintenance parameters..................................................................................................... 70
2.2 Starting and Charging System....................................................................................................... 71
2.2.1 Storage Battery................................................................................................................... 71
2.2.3 Charging System.................................................................................................................72
Chapter 3 Engine Electronic Control System........................................................................................... 76
3.1 Attentions.......................................................................................................................................76
Engine Maintenance Manual
3.1.1 Common maintenance precautions.....................................................................................76
3.1.2 Diagnostic tool....................................................................................................................77
3.1.3 Engine OBD System Cautions............................................................................................77
3.2 Structure Principle and Maintenance of the Engine Control System......................................... 80
3.2.1 System description..............................................................................................................80
3.2.2 Electronic control system components............................................................................... 80
3.2.3 Vehicle diagnostic system.................................................................................................. 83
3.2.4 Engine fault diagnosis.........................................................................................................86
3.3 Structure Principle and Maintenance of the Engine Electric Components....................................94
3.3.1 Air inlet temperature pressure sensor................................................................................. 95
3.3.2 Coolant temperature sensor................................................................................................ 97
3.3.3 Electronic throttle valve......................................................................................................99
3.3.4 Hall sensor........................................................................................................................ 101
3.3.5 Oxygen sensor...................................................................................................................103
3.3.6 Fuel injector...................................................................................................................... 105
3.3.7 Knock sensor.....................................................................................................................106
3.3.8 Continuously variable CAM phase regulator and control valve.......................................108
3.3.9 Carbon canister solenoid valve......................................................................................... 110
3.3.11 Ignition coil.....................................................................................................................113
3.3.12 Spark plug....................................................................................................................... 116
3.3.13 On-off Water Pump........................................................................................................ 118
3.3.14 ECM................................................................................................................................119
3.4 Engine Control System Common Fault Diagnosis...................................................................... 123
3.4.1 Electronic control system common failure and main causes............................................123
3.4.2 Electronic control system common fault diagnose........................................................... 124
3.5 Engine Control System Fault Diagnosis Process.........................................................................131
3.5.1 Diagnose according to the fault code................................................................................131
Engine Maintenance Manual
1
Abbreviation definition
Mil
：
fault lamp
SVS
：
System fault light
DTC
：
fault code
ECM: Engine control module
ECU: Electronic control unit
PWM: Duty cycle signal
ETC
：
Electronic Throttle valve Control
TPS1
：
Throttle valve position sensor signal 1
TPS2
：
Throttle valve position sensor signal 2
APP1: Electronic throttle foot pedal position sensor signal 1
APP2: Electronic throttle foot pedal position sensor signal 2
OFF
：
close
OBD: Vehicle diagnostic system
ROM: Read Only Memory
RAM: Read and write memory
VVT
：
Variable Valve Timing
VCP
：
Variable Cam Phaser
OCV
：
Oil control valve
Delphi
：
Delphi system
CTS
：
Coolant temperature sensor
MAT
：
intake air temperature
MAP
：
intake air pressure
RPM
：
Revolutions Per Minute
Unit:
1MPa=10bar=1000KPa
1V=1000mV
1Kg=1000g
1Min=1 minute
Engine Maintenance Manual Engine machinery
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Chapter 1 Engine Machinery
1.1 Engine main technical specifications and parameters
1.1.1 Main technical specifications
Engine model
HFC4GB2.3D
HFC4GB3.3D
Engine type
Inline four cylinders
、
double
overhead camshafts
、
16 air
valves
、
DVVT
Inline four cylinders
、
double
overhead camshafts
、
16 air
valves
、
DVVT
Working method
Four-stroke, homogeneous
combustion
Four-stroke, homogeneous
combustion
Emission level
China V
China V
Fuel type
Gasoline
Gasoline
Idling rotation speed
（r/min ）
750±30
750±30
Rated power(Kw)
85
88
Rated rotation speed
（
r/min
）
6000
6000
Maximum
torque(N.m)
150
155
Maximum torque
speed
（
r/min
）
3500-4500
3500-4500
Total load minimum
fuel
consumption(g/kW· h)
245
245
Displacement（ml）
1449
1590
Compression ratio
10.5
10.5
Cylinder diameter
75
75
Stroke(mm)
84.8
90
Crankshaft Rotating
direction
Counterclockwise
Counterclockwise
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Ignition sequence
1-3-4-2
1-3-4-2
Driving mode
Electrical power start
Electrical power start
Lubrication method
Pressure and splash composite
Pressure and splash composite
Cooling form
water cooling
water cooling
Whole machine
weight (kg)
90
90
1.1.2 Main parts specifications
Main parts parameter table
Parts name
Technical characteristics
Engine oil filter
Full flow rotary filter Thread specification
M20×1.5-6H
Engine oil pump
Internal rotator type
Cooling water pump
Switch-type coolant pump
Thermostat
wax type Opening temperature:82
℃
full
open temperature:95
℃
Generator
Internal regulator ac generator
specification:14V 110A
spark plug
Iridium platinum alloy type
oil pressure guide rail
No oil return
1.1.3 Main inspection and adjustment parameters
Main inspection and adjustment parameters table
Valve clearance
（
mm
）
intake valve 0.20±0.03 exhaust valve 0.30±0.03
Emission standard
China V
Engine oil temperature
≤135℃
Water temperature
≤110℃
sparking plug electrode
gap
0.7～0.8mm
1.1.4 Bolt torque table
Name
Specification
Quantity
Tightening torque (N · m)
High strength bolts
Main bearing cover bolt
M9×1.25×74.5
10
（
35±2
）
N·m+60°
～
64°
Connecting rod bolt
M6×0.75×33
8
5N·m→10N·m→13N·m+45°+45°
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camshaft bearing cover bolt
M6×1×35
16
11±1
camshaft front bearing
cover bolt
M8×1.25×30
3
20±1
Cylinder head bolt
M9×1.25×143.
5
10
（
24.5±2
）
N·m+180°
～
184°
crankshaft belt pulley bolt
M14×1.5×54
1
(50±2)N·m+(60±2)°
Flywheel bolt
M11×1.25×25
6
100±5
Exhaust valve timing
regulator bolt
M10×41
1
100±5
Intake valve timing
regulator bolt
M10×41
1
100±5
E-type bolt
Crankshaft rear oil seal bolt
M6×10 E8
6
7.6±0.6
rear lifting lug bolt
M8×20 E10
2
18.4±1.4
air inlet manifold bolt
M8×40 E10
5
18±1.0
oil pan bolt
M6×12 E8
16
11±1.0
sprocket chamber cover bolt
Ⅰ
M10×90 E14
2
39.5±3.0
sprocket chamber cover bolt
Ⅱ
M10×50 E14
2
39.5±3.0
sprocket chamber cover bolt
Ⅲ
M6×30 E10
2
8.4±0.6
M6×20 E10-type bolt
M6×20 E10
6
8.4±0.6
M6×12 E10-type bolt
M6×12 E10
7
8.4±0.6
M6×45 E10-type bolt
M6×45 E10
2
8.4±0.6
M6×25 E10-type bolt
M6×25 E10
9
8.4±0.6
M6×12 E8-type bolt
M6×12 E8
1
8.4±0.6
cylinder head guard bolt
M6×27 E10
10
9±1.0
engine oil filter bracket bolt
M8×30 E12
2
20±1
blower water return steel
M6×20 E8
2
7.6±0.6
Engine Maintenance Manual Engine machinery
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tube bolt
oil pressure guide rail bolt
M8×35 E12
2
18.4±1.4
plug
Main oil duct plug
Ⅰ
Inner hexagon
M20
2
60±5
Main oil duct plugⅡ
Inner hexagon
M12
1
35±5
WATER DRAIN SCREW
PLUG
Inner hexagon
M12
1
25±5
oil duct plug
Inner hexagon
M10
1
20±2
VVT oil duct plug
M14×1.5×14
1
44±5
Oil drain plug
M14×1.5×14
1
39±5
other bolt
fixed track bolt assy.
M6×1×12
2
10±2
Movable track bolt assy.
M8×1.25×15
1
23.5±4.5
starter bolt
M8×55
2
24±3
engine oil pressure switch
R 1/8
1
10±2
spark plug
M14
4
25～30
exhaust manifold stud bolt
M8×1×12
5
12±2
Q1840816(exhaust
manifold bracket bolt)
M8×16
2
20～25
CATALYTIC
CONVERTER THERMAL
INSULATION COVER
NUT
M6×1
3
10±1
Crankshaft signal wheel
bolt
M6
3
12.5±2.5
Water temperature sensor
1
20±4
hall sensor bolt
Inner hexagon
2
8~10
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M6×1×16
knock sensor bolt
Inner hexagon
M8×1.25×30
1
20±4
exhaust manifold nut
M8
5
35±2
throttle valve self-tapping
bolt
Inner hexagon
spline
M6×1×25
4
8~10
square head bolt
M10×1.25×90
1
47±5
idle gear bolt
M10×1.25×38
1
49±9
Oxygen sensor
2
35±5
Engine oil filter
1
Rotate three quarters of the circle
after installation surface contact or
11±1N.m
idle gear assy.
M10×1.5
1
50±5
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1.1.4 Maintenance limitation
Items
Standard value
Limit Value
Camshaft
Camshaft height (mm)
Air inlet
44.7054±0.1mm
Exhaust
44.2836±0.1mm
Cylinder head and air valve
Cylinder head surface flatness (mm)
Below 0.03
0.1
Cylinder head total height (mm)
112.9～113.1
Air valve edge thickness (mm)
air inlet door
3.0
0
35.1
0.85
exhaust valve
1.85±0.15
1.35
Clearance between air stem and
air valve guide pipe
（
mm
）
Air inlet
0.020
～
0.036
0.10
Exhaust
0.030～0.045
0.15
Valve taper angle
45°～45.5°
Air valve total total length
air inlet door
89.61
89.11
exhaust valve
90.94
90.44
Free height of each valve spring（mm）
43.1
42.7
Valve spring loading/installing height
（
N
）
/
（
mm
）
152×33.4
310×25.2
The first air ring sideshake
（
mm
）
0.03
～
0.07
0.10
The second air ring sideshake（mm）
0.02～0.06
0.1
The first air ring open clearance（mm）
0.15～0.30
0.8
The second air ring open clearance（mm）
0.30～0.50
0.8
Combined oil ring open clearance
（
mm
）
0.10
～
0.60
1.0
Piston pin external diameter （mm）
18.002～18.005
Connecting rod journal clearance（mm）
0.02～0.04
0.1
Big head side clearance of connecting rod
0.10～0.30
0.4
Crankshaft axial clearance
（
mm
）
0.09
～
0.27
Crankshaft main journal diameter （mm）
46.004～46.029
Connecting rod shaft journal diameter（mm）
39.982～40.0
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Crankshaft main journal diameter clearance（mm）
0.02～0.04
Cylinder head surface flatness (mm)
Below 0.03
Cylinder body total height (mm)
280
Cylindricity of cylinder body
0.007
Cylinder hole inner diameter (mm)
75.000～75.015
Clearance between piston and cylinders
（
mm
）
0.02
～
0.04
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1.2 Engine body
1.2.1 Common precautions
1. Precautions for discharging engine coolant
Discharge engine coolant after engine is cooling.
2. Precautions for disconnect fuel tube
1) before starting work, make sure there is no object in the working area that will cause combustion
or spark.
2) Release the fuel pressure before disconnection and disassembly.
3) Disconnect the pipe and plug the opening to prevent fuel leakage.
3. Precautions for disassembly
1) When a dedicated service tool is required, please use a dedicated service tool. Please always pay
attention to safety work and do not operate without following the instructions.
2) Take special care not to damage mating or sliding surfaces.
3) If necessary, block the opening of the engine system with tape or the like to prevent foreign
objects from entering.
4) Organize the disassembled parts systematically for troubleshooting and reassembly.
5) The basic principle for loosening the bolts and nuts is to loosen the outermost part and then
release its diagonal position. If you have specified a release order, please follow the order specified.
4. Precautions for inspection, maintenance and disassembly
Before repair or replacement, thoroughly inspect the parts and replace if necessary.
5. Precautions for assembly
1) Tighten the nuts and bolts with a torque wrench.
2) The basic principle of tightening the bolts and nuts is to tighten the middle with multi-step with
the same degree of tightness, then tighten the internal and external diagonal position. If you have
specified a release order, please follow the order specified.
3) Replace with new liner, oil seal or "O" ring.
4) Rinse thoroughly, clean and dry each part. Carefully check engine oil or engine coolant lines for
any blockage.
5. Do not damage the sliding surface and matching surface. Thoroughly remove foreign materials
such as fabric debris or dust. Before assembly, lubricate the sliding surface with oil.
Engine Maintenance Manual Engine machinery
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6) After draining the engine coolant and refilling, release air from the line first.
7) After repair, start the engine and increase the engine speed Check the engine coolant, fuel, engine
oil and intake and exhaust leaks.
6. Parts with the setting tightening angle
1) Final angle tightening of the following engine components:
1 cylinder head bolt
2 main bearing cover bolt
3 Connecting rod cover nut
2) Do not make the final torque according to the torque value.
3) The torque values for these parts apply to the pretensioning step.
4) Make sure thread and base surface are clean and oil is applied.
1.2.2 Precautions for sealant
1. Remove the sealant
After removing the retaining nut and
bolt, separate the
mating surfaces using a scraper and remove
the old sealant.
note:
■ Be careful not to damage mating
surfaces.
■ Insert the squeegee and tap it to slide
it sideways as
shown.
■Where the scraper is difficult to use, please use a rubber hammer to tap the parts for removal.
■ If you have to use tools such as a
screwdriver, be
careful not to damage the mating surfaces.
2. Sealant application steps
1) Use a squeegee to remove the old
sealant attached
to the pad application surface and mating
surface.
note:
■ Thoroughly remove the old sealant from the grooves, fixing bolts and bolt holes in the sealant
application surface.
2) Wipe clean sealant application surface and mating surface with unleaded gasoline, remove the
attached water, grease and foreign matter.
Engine Maintenance Manual Engine machinery
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3) Place the specified size of the sealant completely in the designated location.
■If there is a groove for the sealant,
please put the
sealant into the groove.
■ For bolt holes, please place the sealant
inside the
hole.Occasionally use outside the hole.
■Install the binding element within 5
minutes of
applying the sealant
■If there is a stain on the sealant,
remove it
immediately.
■ Do not retighten the bolts or nuts after
installation.
■ Thirty minutes after installation, refill
with engine oil
and engine coolant.
note:
■If there are any special instructions in this manual, please follow the instructions.
1.2.3 Preparation work
1、Maintenance tool
Special tools chart
Seri
al
No.
tool
Outside view
Description
1
Flywhee
l stop
Fixed flywheel
2
Air
valve
spring
compres
sor
Compression air
valve spring
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3
Oxygen
sensor
sleeve
Remove and
install oxygen
sensor
4
Oil pan
remover
Remove oil pan
5
Air
valve oil
seal
installin
g device
Install air valve
oil seal
6
Camshaf
t oil seal
installin
g device
Installing
camshaft oil seal
7
Cranksh
aft front
oil seal
director
Guide when
installing
crankshaft front
oil seal
8
Cranksh
aft front
oil seal
installer
Install crankshaft
front oil seal
Engine Maintenance Manual Engine machinery
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9
Cranksh
aft rear
oil seal
installin
g device
Install the
crankshaft rear oil
seal
10
Piston
pin
locating
tool
Install and remove
piston pin
11
guide
sleeve
Coordinate with
piston pin locating
tool
12
Elastic
belt
tools
Install the elastic
belt
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2、Sealing and fastening adhesive for engine assembly
Sealing part
sealant
Crankshaft rear oil seal
assembly-engine body
Dow Corning 3-0115 plane
sealant
Threebond 1217G
Tonsan 1590
Oil pan-engine
body-crankshaft rear oil seal
assy.
Dow Corning 3-0115 plane
sealant
Threebond 1217G
Tonsan 1590
Sprocket wheel cover-engine
body-cylinder head
Dow Corning 3-0115 plane
sealant
Threebond 1217G
Tonsan 1590
Bowl plug - cylinder head
Loctite 12086 Bowl plug
sealant
Crankshaft signal wheel bolt
Loctite 262 thread tighten glue
Water temperature sensor
Tonsan 1243 thread sealing
adhesive
engine oil pressure switch
Tonsan 1243 thread sealing
adhesive
3、Lubricant oil
Type of lubricant oil
Engine oil type
Environment temperature
Quality grade
JAC G01 5W-30
-30℃～40℃
SM and above
JAC G02 5W-30
-30
℃～
40
℃
SN and above
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1.2.4 Engine belt
1、Check elastic belt
Warning:
■Be sure to operate after the engine has stalled.
1）Check whether or not they have aging、cracks、wear and oil stain. If necessary, please replace.
2）Check the belt deflection between the belt wheels at the center point of the belt。
■ It should be carried out when the engine is cold, or it has been shut down for 30min.
note:
■Elastic belt after the engine is running around 15 min, the tension will decay 30%-40% to
reach stability at 330 ~ 330 N, if it continues to decay more than 10% after reaching stability ,
the skid appears, the belt has reached the limit, the belt should be replaced.
note:
■The belt groove should not be wrong with teeth during elastic belt installation, otherwise it will
damage the belt;
Special auxiliary equipment should be used when elastic belt is installed, otherwise it is easy to
cause belt damage.
■When installing the belt, make sure it meshes properly with the belt wheel groove
。
■Do not let engine oil and engine coolant splash on the belt.
■Do not twine or bend the belt too much.
note:
■Make sure the belt meshes properly with the belt wheel groove
。
■Make sure engine oil and engine coolant do not splash on the belt and each pulley groove.
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1.2.5 Air inlet manifold and exhaust manifold
1、elements
Air inlet manifold and exhaust manifold breakdown drawing
1-PCV valve connection hose 2-air inlet manifold bolt 3-charcoal canister solenoid valve connection hose 4-air
inlet manifold seal ring 5-heat shield bolt 6-heat shield 7- exhaust manifold gasket 8-exhaust manifold nut 9-exhaust
manifold 10-exhaust manifold bracket 11-exhaust manifold bracket bolt 12-electronic throttle valve 13-throttle
valve seal ring 14-EGR steel tube 15-EGR valve 16-exhaust manifold
2 Air inlet manifold
1) disassembly
1 Disconnect the wire harness connector of the absolute pressure sensor
2 Disconnect hose connectors below:
■PCV valve connection hose
■Brake vacuum booster hose at the side of air inlet manifold
■Vacuum hose at the side of charcoal canister solenoid valve
3 Disassemble throttle valve self-tapping bolt,take down electronic throttle valve.
4 Remove the fixing bolts of air inlet manifold and intake manifold bracket.
■tightening torque: (22.5±2.5) N·m
5 Disassemble air inlet manifold bolt
14
15
Engine Maintenance Manual Engine machinery
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■tightening torque: (18±1.0) N·m
6 Disassemble EGR valve、EGR steel tube
■tightening torque: (18±1.0) N·m
7 Take down Air inlet manifold assy.
2）Inspection after disassembly
Check whether or not the air inlet manifold has crack or other damage, the mating surface is
deformed, and the air inlet manifold seal ring and throttle seal ring are damaged. If yes,Repair or replace
please.
3) Installation
■Follow the opposite sequence of the demounting sequence.
note:
■Do not reuse the unusable parts
3、Exhaust manifold
1) disassembly
note:
■This operation is performed when the exhaust system is completely cooled
。
1 Disconnect the wire plug of the front oxygen sensor. Remove the front oxygen sensor with a
special tool if necessary.
■tightening torque: (35±5) N·m
note:
■Don't damage the oxygen sensor
。
■Any oxygen sensor that falls from a place more than 0.5m to the hard ground cannot be used
again. Please replace it
。
2 1. Disassemble the fixing bolts of thermal insulation cover I on the exhaust manifold,take down
the cover I.
■tightening torque: (10±1) N·m
3 2. Remove the exhaust manifold bracket bolts, and then take down exhaust manifold bracket.
■tightening torque: (22.5±2.5) N·m
4 Disassemble exhaust manifold nuts,and then take down exhaust manifold.
Engine Maintenance Manual Engine machinery
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■tightening torque: (35±2) N·m
2）Inspection after disassembly
Check whether the exhaust manifold mating surface is deformed or not.
3) Installation
Follow the opposite sequence of the demounting sequence.
note:
■Do not reuse the unusable parts
■Do not over-tighten the oxygen sensor to avoid damaging the oxygen sensor
。
1.2.6 Timing sprocket mechanism
1
、
element
Timing sprocket mechanism breakdown drawing
1-timing chain 2-Exhaust valve timing regulator 3-sprocket bolt 4-Moving rail bolt assembly 5-Moving rail assembly
6-Tensioner bolt 7-automatic tensioner 8-fixing rail assembly 9-fixing rail bolt assembly 10-air inlet
valve timing regulator
2、Timing chain disassembly and assembly
1) disassembly
1 Remove the fixing bolt of water pump belt pulley.
1
2
3
4
5
6
7
8
9
10
Engine Maintenance Manual Engine machinery
19
■tightening torque: (8.4±0.6) N·m
Note: the elastic belt can be disassembled by the friction of the driving belt when elastic belt is not
disassembled.
2 Remove the elastic belt and check whether the elastic belt is worn 、 aged、 cracked, etc.
Replace the elastic belt if necessary.
3 Disassemble oil level gauge assembly。
■tightening torque: (8.4±0.6) N·m
4 Remove crankshaft pulley。
■tightening torque: （100±5）N·m+（90±2）°。
5 Remove the Generator。
6 Remove oil pan and cylinder head shield.
Note: The oil pump housing can only be removed after removing oil pan and cylinder head
shield.
Remove oil pump housing.
7 Check the timing condition.
Note: check whether or not the timing points shown in the diagram meet the requirements.
8 Remove the fixing and moving rails of automatic tensioner and timing chain. And check for
exceptions.
■tightening torque: automatic tensioner (10±1) N·m.
Engine Maintenance Manual Engine machinery
20
fixing rail:（10±2）N·m。
moving rail（23.5±4.5）N·m。
9 Remove exhaust valve timing regulator.
■Bolts’ tightening torque: (100±5) N·m
10 Remove air inlet valve timing regulator.
■Bolts’ tightening torque: (100±5) N·m
2）Assembly
Follow the reverse procedure above for disassembly. Pay attention to the timing points and
installation torques during installation
Oil pump housing installation meets the following requirements:
a. When the oil pump housing is assembled, the glue coating surface should be clean, no oil, dirt,
etc
And gelatinizing with corning 3-0115 surface sealant or equivalent products according to the following
picture. The diameter of the rubber strip at point A is 22mm±0.5mm. The diameter of the rubber strip at
point B is 1.5mm±0.5mm..
Oil pump housing gelatinizing introductions
b. The tightening sequence of oil pump housing bolts should follow the principle: pretightening
first,
then fastening from the middle to both sides crosswise. It is required to tighten the bolts with larger
diameters first and then tighten the bolts with smaller diameters
■Point 1-4 Bolts’ tightening torque: (39.5±3.0) N·m
A
B
Engine Maintenance Manual Engine machinery
21
■Point 5-15 Bolts’ tightening torque: (8.4±0.6) N·m
Oil pump housing bolts tightening sequence
1.2. Camshaft Assembly
1
、
element
Camshaft Assembly breakdown drawing
1-exhaust camshaft 2-mechanical tappet 3-air inlet camshaft 4-Valve timing regulator5-Valve timing regulator bolt
6-OCV valve 7-fastening bolt
Engine Maintenance Manual Engine machinery
22
2、Disassembly and Assembly
1) disassembly
1 Disassemble ignition coil
2 Disassemble cylinder head guard assy.
3 Rotate crankshaft , let cylinder-1 piston stay at the stop point of compression.
4 Measure valve clearance.
a. The valve clearance is measured at position A in the figure
b. If valve clearance does not meet the standards, it needs to be adjusted.
■It is important to note the measurement value as an important parameter to calculate the proper
tappet label.
Standard valve clearance (State of cold machine)
Items
Specified state
Air inlet
（
0.22±0.03
）
mm
Exhaust
（
0.30±0.03
）
mm
6 Turn the crankshaft 360º clockwise , let cylinder-4 piston stay at the stop point of compression.
7 Measure the valve clearance at position B in the figure.
■It is important to note the measurement value as an important parameter to calculate the proper
tapper label.
8 Remove engine front end belt, idler wheel and shock absorbing belt pulley.
9 Remove oil pan and engine oil suction filter.
10 Remove oil pump housing and timing chain.
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23
11
Remove air valve timing regulator.
a. Fix the camshaft with a wrench.
b. Unscrew Intake valve timing regulator bolt.
■Bolts’ tightening torque: (100±5) N·m.
c. Take down air inlet and exhaust valve timing regulators.
12
Remove air inlet and exhaust camshaft.
a. Remove camshaft front bearing cover, in reverse numerical order as shown in the figure below.
b. Remove camshaft bearing cover, in reverse numerical order as shown in the figure below.
13
Measure the height of the camshaft
Air inlet:（44.7054±0.1）mm
Exhaust:（44.2836±0.1）mm
If the measured value is not within the
standard
value, replace the camshaft.
14
Remove the mechanical tappet in the
unqualified valve clearance and adjust the
valve
clearance.
■Mark the removed tappet and the corresponding installation position to prevent forgetting the
position of the column.
Engine Maintenance Manual Engine machinery
24
a. Measure the thickness of the removed mechanical tappet with a screw micrometer.
b. According to the measured valve clearance and the thickness of the old tappet,Calculate the
thickness of the new tappet to make the valve
clearance reach the specified range.
New tappet thickness table
※
Example
Measured intake valve clearance＝0.26mm，marked as A。
Measured old tappet thickness＝2.79mm，marked as B。
Measured intake valve clearance+Measured old tappet thickness ＝The clearance between the
base circle of the camshaft and the top of the valve tappet，marked as C，C＝3.05mm。
C＝Intake valve clearance standard value+Ideal new tappet thickness。 So Ideal new tappet
thickness＝3.05mm－0.22mm＝2.83mm。
■When calculating the thickness of the exhaust side tappet, the above equation should be replaced
with exhaust valve clearance standard value.
c. The closest new tappet thickness ＝2.82mm or 2.84mm。 Select tappet 282 or tappet 284.
d. Select a new tappet with the closest thickness to the calculated value.
■The available tappets have 31 sizes, ranging from 2.70 to 3.30mm, increasing by 0.02mm.
■The identification number in the mechanical tappet indicates the thickness (e.g., 272 indicates the
thickness value of 2.72mm).
Items
specification
Air inlet
new tappet thickness=old tappet thickness+[ measured
valve clearance-0.22mm]
Exhaust
new tappet thickness=old tappet thickness+[ measured
valve clearance-0.30mm]
Engine Maintenance Manual Engine machinery
25
Tappet thickness group table
Tappe
Thickness /mm
Tappe
Thickness /mm
Tappe
Thickness /mm
270
2.70
292
2.92
314
3.14
272
2.72
294
2.94
316
3.16
274
2.74
296
2.96
318
3.18
276
2.76
298
2.98
320
3.20
278
2.78
300
3.00
322
3.22
280
2.80
302
3.02
324
3.24
282
2.82
304
3.04
326
3.26
284
2.84
306
3.06
328
3.28
286
2.86
308
3.08
330
3.30
288
2.88
310
3.10
290
2.90
312
3.12
2）Assembly
1 Install the new tappet selected after the calculation.
■Confirm the specific position of each new tappet selected after calculation (corresponding to the
mounting hole), preferably mark the new tappet.
2 Install the camshaft and bearing cover and pre-tighten the bolts in the opposite order of
disassembly.then tighten in this order.
■Engine oil should be applied to the camshaft journal and cam.
■Camshaft front bearing cover bolts(number 3) tightening torque: (20±1) N·m
■Camshaft bearing cover Bolts(number 16) tightening torque: (11±1) N·m
3 Measure again whether or not the valve clearance after adjustment meets the standard. If it is
beyond the standard range, first check whether the tightening torque of bearing cover bolts meets the
requirements or not.
■The bolt torque meets the requirement,Remove the mechanical tappet in the unqualified valve
clearance and adjust the valve clearance.
■If the tightening torque of bolts does not meet the requirements, loosen all the bolts on this
camshaft and tighten them to the specified torque in order. Measure valve clearance again, if there is any
unqualified clearance,Remove the mechanical tappet in the unqualified valve clearance and adjust the
valve clearance.
4 Install air valve timing regulator.
5 Install timing chain and oil pump housing.
6 Install engine oil suction filter and oil pan.
7 Install front-end power accessory and drive belt.
Engine Maintenance Manual Engine machinery
26
8 Install cylinder head guard、ignition coil.
■Check the sealing ring of cylinder head guard before installation to ensure no loss 、damage 、
scratch、crease and other defects, so as to ensure its sealing performance.
■The cylinder head guard bolts must be pre-tightened and fastened in the order shown in the
figure,Tightening torque：（9±1)N·m。
1.2.8 Cylinder head
1. Maintenance on vehicle (the abnormal parts will be maintained and reinstalled back)
Check cylinder pressure:
1 Turn off the engine after thoroughly warming it up.
2 Release fuel pressure
■Remove the fuel pump fuse from the fuse box.
■Start the engine.
■After the engine is out, start the engine to idle two or three times to release the fuel pressure
completely .
3 Remove ignition coils and spark plugs.
4 Install a spliced cylinder pressure gauge on the spark plug hole.
5 Step the accelerator pedal to the bottom and turn the ignition switch to "START" to start. When
the meter pointer is stable, read the compression pressure and engine speed. Do the above steps to check
the remaining cylinders
Engine Maintenance Manual Engine machinery
27
■Standard pressure: 1200 ± 100kPa.
■Minimum pressure：1100kPa。
■Allowable difference between cylinders：no more than100kPa。
note:
■Prevent foreign matter from entering the cylinder through the inlet
。
■Always use a fully charged battery to get the required engine speed
（
200r/min
）。
■If the compression pressure is below the minimum, check the valve clearance and other related
parts (valve, valve seat, piston, piston ring, cylinder diameter, cylinder head and cylinder head gasket).
After checking, measure the compression pressure again.
■If the compression pressure of some cylinders is low, add 10ml engine oil into the spark plug
hole of the cylinder and re-check the cylinder pressure.
■If the cylinder pressure increases after the engine oil is added, the piston ring may be worn or
damaged Check the piston ring and replace it if necessary.
■If the compression pressure is still low after the engine oil is added,the valve may fail. Check if
the valve is damage. Replace damaged valve or valve seat.
■If the compression pressure of two adjacent cylinders is low and the pressure is still low after
adding oil, the cylinder gasket may leak Please replace cylinder head gasket
6 After the inspection, please install the removed parts.
7 Start the engine and make sure it runs smoothly.
2、Disassembly and Assembly
1) disassembly
1 Release fuel pressure
2 Discharge engine coolant and oil. Refer to "replace engine coolant" and "replace engine oil".
note:
■Be sure to operate after the engine is cooling.
■Do not let engine oil and engine coolant splash on the belt.
3 Remove the following components and related parts:
■cylinder head guard。
■Elastic belt。 Refer to “Elastic belt”.
■Oil pan。
■Oil pump housing and timing mechanism。 Refer to “Timing sprocket mechanism”.
Engine Maintenance Manual Engine machinery
28
■Air inlet manifold。 Refer to “Air inlet manifold”.
■Exhaust manifold。 Refer to “Exhaust manifold”.
■Thermostat housing。 Refer to “Thermostat assy”.
■Engine oil dipstick guide pipe。
4 Unscrew cylinder head bolt.
■Disassemble in numerical order as shown below。
5
1
9
7
8
4
3
10
6
2
5 Remove cylinder head gasket
2）Inspection after disassembly
1 Check whether the cylinder head has cracks or other damage or not.
2 Check whether or not the waterways and oil channels between cylinder body and cylinder head
are blocked, if any, please clean.
3 Check cylinder head flatness
Note: when this inspection is carried out, the flatness of cylinder block should also be checked.
Refer to“cylinder block flatness”
a.Wipe the oil off the cylinder head and clear away sealant and carbon deposition.
note:
■Be careful not to let impurities fall into the cylinder head channel and oil channel
。
b.Measure the flatness in six directions at multiple positions on the bottom surface of the cylinder
head。
Standard value: 0.03mm below
Limit value: 0.10mm
Cylinder head height (new)：（113±0.1）mm
Engine Maintenance Manual Engine machinery
29
If the value is exceeded standard value, please grinding according to the specification. If the value
is exceeded the limit value, please replace according to the specification.
note:
■The total grindable allowance of cylinder head and cylinder block mating surface is no more
than 0.2mm
。
3）Assembly
1 Install new cylinder head gasket
2 Install the cylinder head as follows:
a.Install the washer as shown in the picture
on the right。
b.Apply appropriate amount of engine oil to
the screw position
and washer of cylinder head bolt。
c.Tighten bolts in numerical order as shown in the figure below until each bolt reaches torque (24.5 +
2) N·m。
d.Loosen the bolts completely。
e.Tighten bolts in the order again until each bolt reaches torque
（
24.5±2
）
N·m
。
f.Paint the head of the cylinder head bolt
and cylinder
head (as shown in the right picture)
。
g.According to tighten the sequence,
tighten each bolt
by extra 90 ° twist
。
H.tighten each bolt 90 ° again, check
whether the paint
marks on bolt head aligns with the cylinder
head
。
note:
6
10
2
4
3
7
8
1
5
9
Engine Maintenance Manual Engine machinery
30
■If the bolt tightening Angle is less than 90 °, that means the fastening torque is not enough
。
■If the bolt tightening Angle is more than 90 °, the bolt should be completely removed, and
reinstall again
i.If the cylinder head bolts are replaced during maintenance,maintain according to the above steps a ~
h.
j.If the cylinder head bolts are not replaced during maintenance,maintain according to the order of a、
b、e、f、g、h.
3 Follow the opposite sequence of the disassembly procedures to install.
4）Inspection after assembly
The following are the steps to check oil leakage, lubricant leakage and tail gas leakage:
1 Before starting the engine, please check the level of the engine cooling fluid and engine oil.
2 Turn the ignition switch to the "ON" position (when the engine is off) to check the connection
for fuel leakage.
3 Start the engine. When accelerating the engine ,check the connection again for fuel leakage.
4 Run the engine to check for abnormal noise and vibration.
5 Thoroughly warm up the engine and check for leakage of fuel oil、exhaust gas or any oil/liquid
(including engine oil and engine coolant).
6 After the engine has cooled, recheck the oil/liquid level(including engine oil and engine
coolant). If necessary, refill to the specified level.
1.2.9 Valve
1、elements
Valve element diagram
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31
1-Exhaust Valve Seat Ring 2-Exhaust Valve 3-air inlet valve 4-air inlet valve Seat Ring 5-valve oil seal
6-valve spring lower seat 7-valve spring 8-valve spring upper seat 9-valve lock clamp 10-valve guide pipe
2、Disassembly and assembly
1）Disassembly
1 Use spark plug sleeve to remove spark plug
2 remove the valve lock、valve spring and valve spring seat。
Use the valve spring compressor to compress the valve spring。
CAUTION:
■All the valve, valve spring and other
components that
being removed should be attached with the
label, indicating
the cylinder number and location.
■Store the parts securely.
3 Remove valve oil seal
4 Remove valve seat ring
5 Remove valve guide pipe
2）assembly
1 Install valve guide pipe
2 Install valve seat ring
3 Install valve oil seal
a.Install valve spring lower seat
b.Install new valve oil seal with special
tools..
note:
■Valve oil seal cannot be reused
Engine Maintenance Manual Engine machinery
32
■The valve oil seal must be installed with the correct special tool
4 Install valve
5 Install valve spring
Note: install facing up with paint mark
6 Install air valve spring upper seat
7 Install valve lock clamp
■Install with valve spring compressor。
■After installation, tap the valve stem edge with a rubber hammer to check the installation。
8 Use spark plug sleeve to install spark plug
1.2.10 Cylinder block assembly
1
、
element
Cylinder block assembly breakdown drawing
1-main bearing cover bolt 2-main bearing cover 3-Main bearing lower bush 4-Main bearing upper bush
5-Cylinder block 6-Crankshaft rear oil seal assembly 7-Crankshaft rear oil seal bolt8-thrust plate
9-flywheel bolt 10 flywheel 11-Crankshaft 12-Crankshaft signal wheel positioning sleeve 13-Crankshaft
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33
signal wheel 14-Crankshaft signal wheel bolt 15-crankshaft pulley 16-Crankshaft pulley baffle ring 17-Crankshaft
pulley bolt
2、Disassembly and assembly
1）Disassembly
1 Remove the following engine accessories. Refer to the relevant chapters for details of the
disassembly process.
■Engine air inlet manifold and engine exhaust manifold。
■Generator belt。
■Generator。
■Engine timing mechanism。
■Water pump。
■water pipe components。
■Generator fixing bracket、air condition compressor fixing bracket。
■ignition coil。
2 Fix the engine overall.
3 Discharge engine oil Refer to “Replace the Engine Oil”.
4 Remove flywheel assembly. Please use the special tool to fix the flywheel and then remove the
fixing bolt.
note:
■Fixing bolts should be loosened in diagonal order
。
5 Remove crankshaft rear bearing
note:
■Once the rear bearing of crankshaft is disassembled, it cannot be used again. Please replace it
with a new one
。
6 Remove the following system. Refer to the relevant chapters for details of the disassembly
process.
■Cylinder head
■Oil pump housing
■Oil pan
7 Remove knock sensor
note:
Engine Maintenance Manual Engine machinery
34
■Do not drop or tap the sensor
。
8 Remove rear oil seal bracket.
■The driver is inserted between the crankshaft and the rear oil seal housing for disassembly。
note:
■Once the rear oil seal is disassembled, it cannot be used again. Please replace it with a new one
。
9 Remove piston and connecting rod assembly
Before removing piston and connecting rod assembly,Please check the clearance of the connecting
rod head. Refer to “inspection after disassembly" below.
a. Rotate the crankshaft. Place the corresponding crankshaft of the connecting rod to be removed
in the center of the bottom.
Note: For ease of reinstallation, a cylinder number can be printed on the side of the removed
connecting rod head.
b.Remove connecting rod cover.
■Connecting rod bolts shall be used only once and shall not be reused.
c.Use a rubber hammer or similar tool to push the piston and connecting rod assembly out of the
cylinder block.
note:
■Be careful not to let the connecting rod head damage the cylinder wall and crankshaft journal
。
10 Remove the connecting rod bearing bush from the connecting rod and the connecting rod
cover.
note:
■Identify installation locations and keep them in place without confusion.
11 Remove piston ring from piston.
Check the side clearance of the piston ring before removing it. Refer to “inspection after
disassembly" below.
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35
CAUTION:
■using piston ring expander
。
Engine Maintenance Manual Engine machinery
36
12
Remove the piston from connecting rod as follows：
a.Insert the push rod (special tool) from the arrow mark side in the front
and install guide sleeve D.
B.place the piston front mark up
and install the piston and connecting rod assembly on the piston pin mounting base
(special tool)
c.Press the piston pin out with the press machine.
d.Separate the connecting rod and piston from the piston
and the connecting rod assembly
note:
After removing piston pin, put the piston, piston pin and connecting rod together in the same
cylinder. Do not mix with the piston, piston pin and connecting rod of other cylinders.
13
Remove crankshaft main bearing cover
Before releasing the crankshaft bearing cover, measure the crankshaft axial clearance. Refer to
“inspection after disassembly" below. Please loosen the main bearing cover bolts of crankshaft in
numerical order as shown in the figure below
1
2
3
4
5
6
7
8
9
10
Engine Maintenance Manual Engine machinery
37
As shown in the picture on the
right,When
disassembling, the crankshaft bearing cover
bolts can be
used to shake the crankshaft bearing cover
backwards and
forwards to disassemble it.
14
Remove crankshaft
15
Remove crankshaft signal wheel
■Crankshaft signal wheel bolts are removed clockwise。
2）Inspection after disassembly
1 Crankshaft axial clearance
Use the driver to lever the
crankshaft,record the reading of the dial
indicator at the
same time.
Standard : 0.09～0.27mm
If the measured value is not within the standard value, Please replace the thrust plate and remeasure
it。 If it is still not within the standard range , please replace the crankshaft.
2 Connecting rod big head clearance
Measure the clearance between the
connecting rod
and the crankshaft arm with a feeler gauge.
Standard clearance: 0.10～0.30mm
Limit value: 0.4mm
If the measured value exceeds the limit,
replace
connecting rod and measure again. If the limit is still exceeded, replace the crankshaft.
3 piston ring side clearance
Measure the clearances between piston ring and piston ring grooves with a feeler gauge.
Standard:
First groove：0.03～0.07mm
Second groove：0.02～0.06mm
limit:
Engine Maintenance Manual Engine machinery
38
First groove：0.10mm
Second groove：0.10mm
If the measured value exceeds the limit, replace piston ring and measure again. If the limit is still
exceeded, replace the piston ring.
4 piston ring opening clearance
Make sure the cylinder inner diameter is within the specified range Refer to “Cylinder cylindricity”.
Lubricate the piston and piston ring with engine oil and insert the piston ring until the piston reaches
the middle of the cylinder,and use feeler gauge to Measure piston ring opening clearance.
Standard:
First groove：0.15～0.30mm
Second groove：0.30～0.50mm
Combined oil ring: 0.10～0.60mm
limit:
First groove：0.8mm
Second groove：0.8mm
Combined oil ring: 1.0mm
If the measured value exceeds the limit, replace piston ring and measure again. If the limit is still
exceeded, replace the cylinder block.
5 Cylinder block flatness
Clean the liner on the cylinder block surface, as well as engine oil 、 scale 、 carbon or other
contaminants.
note:
■Be careful not to let gasket chips fall into engine oil or engine coolant.
The flatness of cylinder block is measured with a ruler and a feeler gauge in six different directions.
Standard value: 0.03mm below
Limit value: 0.1mm
If the limit is exceeded, replace the
cylinder block.
Engine Maintenance Manual Engine machinery
39
6 Connecting rod journal clearance
note: use plastic wire gauge for measurement.
a.Remove all engine oil from the connecting rod journal and the connecting rod bearing bush.
b.Place the plastic wire gauge on the
connecting rod
journal and cut it into the same length as the
width of the
bearing bush. plastic wire gaugemust be at
the center of
connecting rod journal and parallel to its
axis.
c.Gently place the connecting rod
cover in its
position and tighten the bolts to the
specified torque.
d.Remove the bolts and slowly remove the connecting rod cover.
e.Measure the extruded part of the plastic wire gauge at the widest point using a ruler printed on the
plastic wire gauge bag.
Standard value:0.02~0.04mm
Limit value: 0.10mm
f.Remove the plastic clearance gauge completely after measurement.
If the clearance is greater than the limit, replace the connecting rod bearing bush. Replace the
crankshaft if necessary.
7 Crankshaft main journal diameter
clearance
a. Clean the engine oil of crankshaft
journal
and inner surface of bearing bush.
b. Install bearing bush.
c. Cut the length of the plastic wire
gauge to
match the width of the bearing bush Then
place it on the
journal along the axis of the journal.
d. Lightly install the crankshaft bearing cover and tighten the bolts to the specified torque.
e. Remove the bolts and gently remove the crankshaft bearing cover.
f. Measure the extruded part of the plastic wire gauge at the widest point using a ruler printed on
the plastic wire gauge bag.
Standard value:0.02~0.04mm
Limit value: 0.10mm
If the clearance is greater than the limit, replace the main bearing bush. Replace the crankshaft if
Engine Maintenance Manual Engine machinery
40
necessary.
3）assembly
1 Preassemble crankshaft signal wheel
■Ensure no engine oil in the threaded hole of crankshaft signal wheel when assembling.
■Crankshaft signal wheel screw must be coated with Loctite 262 thread fastener or equivalent
product before installation
■Crankshaft signal wheel bolts are tightened counterclockwise as shown in the figure below
2 Blow engine coolant and engine oil out of cylinder block, cylinder diameter and crankshaft
box ,remove foreign matter.
note:
■Use goggles to protect your eyes.
3 Install main bearing bush upper bearing bush
note:
■elect the bearing bush according to the identification mark or color code of the crankshaft
(refer to the assembly table of the main bearing bush). If it cannot be identified, the crankshaft
diameter should be measured and the corresponding bearing bush should be selected to match it.
There are grouping marks on the crankshaft, marking a total of 10 digits. The first 5 digits
correspond to the 1st to 5th main journals respectively. The 6th bit printing: "B", indicating the end of
main journal grouping and the beginning of connecting rod journal grouping; The 7th to 10th bits
correspond to the 1st to 4th connecting rod journals respectively.
connecting rod bearing bush project(start and stop model)
Engine Maintenance Manual Engine machinery
41
connecting rod bearing bush project(non-start-stop model)
The exhaust rear end of the lower end face of cylinder block is marked with the dimension mark of
the main shaft hole, corresponding to the dimension of the 1st to 5th main shaft hole respectively.
Engine Maintenance Manual Engine machinery
42
Main
bearing
hole (mark)
Main bearing bush shall be selected according to the following table
Main bearing bush installation table
■When installing, aim the protrusion of the bearing bush at the cutting of the cylinder block and the
main bearing cover.
■Make sure the engine oil hole on the cylinder block is aligned with the oil hole on the
corresponding bearing bush
4 Install crankshaft to cylinder block. When rotating the crankshaft by hand, please check
whether the rotation is flexible or not.
■Before installing crankshaft, appropriate amount of engine oil should be applied to the inner part
of upper bearing bush.
Main bearing
hole grouping
mark position
Crankshaft grouping marks
1
2
3
4
5
0(up／down）
Black
／
Black
Black
／
yellow
Black／red
Black
／
white
Black
／
purple
1(up／down）
Yellow
／
Black
Yellow
／
Yellow
Yellow／red
Yellow
／
white
Yellow
／
purple
2(up
／
down
）
Red
／
Black
Red／
Yellow
Red
／
Red
Red
／
white
Red／
purple
Engine Maintenance Manual Engine machinery
43
5 Install thrust plate
Install oiled thrust plate in installation groove side of the main bearing seat(fourth), 100% measure
and ensure that the crankshaft axial clearance is 0.09 ~ 0.27 mm, when installing two thrust surfaces
ensure that the flat side joint fourth position, with groove side facing the cylinder holes.
Fourth
gear
thrust
plate
Side with
groove
Flat
side
6 Install main bearing cover
■The main bearing cover can be
identified by
identification marks
■Starting from the front end (timing belt side), install the main bearing cover in order of number
■The arrow must point to the front
7 Tighten the main bearing cover bolts as shown in the figure below
9
2
7
8
5
6
3
1
10
4
a.Apply engine oil to the thread and fixed surfaces of the main bearing cover bolts
Engine Maintenance Manual Engine machinery
44
b.Tighten the main bearing cover bolts in several steps
■Bolts’ tightening torque: (35±2) N·m+60°
～
64°。
■After installing the main bearing cover bolts, make sure the crankshaft can be rotated flexibly by
hand
■Check crankshaft axial clearance Refer to “Crankshaft axial clearance”
8 Preassemble piston connecting rod assembly
■When installing the piston pin, make sure the top of the piston marked forward and the connecting
rod marked forward are the same.
a.Measure the following lengths（As shown in diagram below）
A：Dimensions from piston boss to piston boss outside
B：Dimensions from piston boss to piston boss inside
C：Piston pin length
D：Connecting rod small end thickness
b.The measured value is putted into the following formula：
L=[（A-C）-(B-D)]/2
c.Insert the push rod (special tool) into the piston pin and install guide sleeve A (special tool)。
d.When piston and connecting rod are installed, the front marks should be on the same side。
e.Apply engine oil to the outer ring of the piston pin。
f.Starting with guide sleeve A, press guide sleeve A ,piston pin and push rod into the front marking
side of the piston successively。
g.Screw guide sleeve B into guide sleeve
A, and the gap
between the two sleeves is 3mm plus the L
value
calculated in step 2。
h.Install the piston and the connecting rod
on the piston
pin mounting base in a downward marked
state in front of
the piston。
C.install the piston pin with the press
machine.
note:
■If the pressure distribution load exceeds the specified limit, the piston pin and the piston
assembly and the connecting rod shall be replaced, or both shall be replaced
Standard value: 108±54N·m
Conne
cting
Pi
st
Pis
ton
pin
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45
9 Install piston ring.
■Be careful not to damage the piston when installing piston rings
■Be careful not to damage the piston ring because of overextending
a. Install oil ring
Install the oil liner ring into the piston ring groove Then install the oil ring body
When installing the ring body, put one end of the ring body into the groove by hand, and then press
the rest into the position.
note:
■Do not use piston ring expander to install ring body, otherwise it may lead to wiper blade
fracture
After installing the combined oil ring body, check whether it can move smoothly in both
directions
b. Install1st and 2nd air ring
Install the air ring with the piston ring expander. The identification mark on the air ring should
be toward the top of the piston
c. Piston ring opening direction
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46
10 Install the connecting rod bearing bush on the connecting rod and the connecting rod cover
■Apply engine oil to the surface of the connecting rod bearing bush before installing it。
■Connecting rod bearing bush shall be installed with special tool to ensure the installation position:
as shown in the figure below, the difference between A and B length is less than 0.5mm。
11
Install piston connecting rod assembly on crankshaft
■Rotate crankshaft journal corresponding to the connecting rod to be removed in the center of the
bottom.
■Apply engine oil to cylinder diameter, piston and crankshaft journal。
■Install the connecting rod to the corresponding cylinder hole according to the mark on the
connecting rod
■Make sure the mark on the top of the piston is pointing forward
■Using the piston guide tool, put the piston connecting rod assembly into the guide tool from the
cylinder fire surface and press the piston into the cylinder block with the rubber rod.
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47
CAUTION:
■Be careful not to let the connecting rod head damage the cylinder wall and crankshaft journal。
12 Install connecting rod cover
13 Tighten connecting rod bolts, according to the “5N·m→10N·m→13N·m+45+45°” approach
to tighten alternately.
note:
■Before installing the bolts, apply engine oil to the threaded parts and seating surfaces.
■After installing the piston connecting rod assembly, rotate the crankshaft to check whether the
crankshaft can rotate flexibly or not.
14 Install the rear oil seal bracket with the crankshaft rear oil seal on the cylinder block Use
special tools to press the rear oil seal on the rear oil seal bracket
■When installing crankshaft rear oil seal bracket, ensure that the coating surface is clean, no oil, dirt,
etc., apply Dow corning sealant 3-0115 or equivalent product on the surface of the cylinder block
back-end as shown below, the sealant can also be applied on the corresponding position of crankshaft
rear oil seal bracket. Rubber strip diameter
（
2±0.5
）
mm
。
Apply lubricating oil to the rear oil seal lip and
crankshaft joint, Be careful not to scratch the oil seal when installing.
■Bolts’ tightening torque: (7.6±0.6) N·m
JAC-T3F005
Picture
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48
Crankshaft rear oil seal glue line
15
Install knock sensor
■Bolts’ tightening torque: (20±4) N·m
Note: make sure there is no foreign matter between cylinder block and knock sensor.
16
Install flywheel
■Bolts’ tightening torque: (100±5) N·m
note:
■Follow the principle of pre - tightening first and then symmetrical cross - tightening
。
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1.3 Engine lubricating system
1.3
、
Installation precautions
Sealant application steps:
1、Use a squeegee to remove the old sealant attached to the pad application surface and mating
surface.
note:
■ Thoroughly remove the old sealant from the grooves, fixing bolts and bolt holes in the sealant
application surface.
2、 Wipe clean sealant application surface and mating surface, remove the attached water, grease and
foreign matter.
3、 Place the sealant in the designated location.
1）Install the binding element within 5 minutes of applying the sealant
2）If there is a stain on the sealant, remove it immediately.
3） Do not retighten the bolts or nuts after installation.
4） Thirty minutes after installation, refill with engine oil and engine coolant.
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1.3.2 Engine oil
1. Inspection
1）Engine oil level
Note: before starting the engine, stop the car horizontally and check the engine oil level. If the
engine has started, turn off the engine and
wait for 10min
to check again.
1 Pull out engine oil dipstick and
wipe it clean.
2 Insert the engine oil dipstick and
make sure the
oil level of the engine is within the range as
shown in the
figure.
3 Please adjust it if it is out of the range.
2）Engine oil appearance
1 Check engine oil for white turbidity or serious contamination.
2 If engine oil is turbid or contaminated, it is likely to be contaminated by engine coolant. repair
or replace damaged parts.
3）Engine oil leakage
Check for oil leakage around the following areas:
■Oil pan
■Oil pan oil drain bolt
■Engine oil pressure switch
■Engine oil filter
■The mating surface of cylinder block and cylinder head
■Front and rear crankshaft oil seal
■The mating surface of cylinder block and oil pump
■The mating surface of cylinder head guard and cylinder head
■Front and rear camshaft oil seal
4）oil pressure checking
note:
■The engine oil is very hot, be careful not to get scalded.
■Check the oil pressure after parking.
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1 Check the oil level
2 Lift the vehicle, disconnect the wire
connector of
engine oil pressure switch and remove the
switch.
3 Install oil pressure gauges and hoses
4 Start the engine and warm it to
normal working
temperature.
5 Check oil pressure during engine running with no-load
Note: when the engine oil temperature is low, the oil pressure increases.
■If there is any obvious difference, please check the oil pipeline and oil pump for leakage.
6 After inspection, install the pressure switch as follows:
a.Remove old sealant that is attached to pressure switches and engines
b.Use sealant as required and tighten pressure switch
■Please use the specified sealant：Tonsan 1243 thread sealing adhesive
■Bolts’ tightening torque: (10±2) N·m
c.After warming up the engine, make sure there is no oil leakage when the engine is running
normally.
2
、
Replace the Engine Oil
1 Start engine and preheat until the engine coolant temperature reaches (80 ~ 90 ℃).
2 Remove engine oil filler cover from the cylinder head guard.
3 Remove the drain screw plug from the oil pan to drain the oil The oil discharge time shall not
be less than 15min.
note:
■The engine oil is very hot, be careful not to get scalded.
4 Use special spanner to disassemble the oil filter;
5 Clean filter installing surface on oil filter bracket.
6 Replace the new oil filter:Apply a small amount of oil to the o-ring of the oil filter. When the
o-ring of the oil filter touches the flange of the oil filter holder, use a special wrench to twist 3/4 circles
or equal to (11 + 1) N·m.
7 Install oil duct screw plug on the oil pan.
■Bolts’ tightening torque: (39±5) N·m
8 Inject the oil from the oil inlet on the cylinder cover guard, about 4L.
9 After starting the engine without load and running for (2-3) min, check the interface between
filter and bracket to ensure no oil leakage.
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52
10 Turn off the engine and wait for 10min to check whether the oil level is between the upper and
lower scale. If oil is insufficient, please add.
■Measurement method of the engine oil: when measuring, Cars should be parked horizontally,
after the oil level of oil is stable, pull out oil dipstick, wipe engine oil with a clean cloth, then insert it in
oil pan to measure the oil level The engine oil level shall be kept in the middle and upper part of two
scale lines of the oil dipstick. The height of oil level should also be checked before leaving the vehicle
and every driving (300 ~ 500)km. If the oil quantity is insufficient, it should be added timely.
1.3.3 Engine Oil Filter
1
、
Disassembly and Assembly
1) disassembly
Use special tools to disassemble the oil filter;
note:
■Use original jianghuai oil filter
■The engine oil is very hot, be careful not to get scalded.
■When disassembling, prepare a cloth to dry the leaking or splattering engine oil.
■Do not let the engine oil stick to the drive belt.
■Thoroughly dry the engine oil spilled on the engine and the car
2)MOUNTING
1 Clean filter installing surface on oil filter bracket.
2 Replace the new oil filter:Apply a small amount of oil to the o-ring of the oil filter. When the
o-ring of the oil filter touches the flange of the oil filter holder, use a special wrench to twist 3/4 circles
or equal to (11 + 1) N·m.
note:
■The oil filter must be tightened with the filter wrench
■If the filter is tightened by hand, oil may leak due to insufficient tightening torque.
2
、
Inspection after assembly
1
）
After starting the engine without load and running for (2-3) min, then check the interface between
filter and bracket ,engine oil should not leak.
Turn off the engine and wait for 10min,then check whether or not the oil level is between the upper
and lower scale. If the oil is insufficient, please add.
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1.3.4 Oil pan and Oil pump
1. Disassembly
1
）
Discharge engine oil.
2
）
Remove oil pan.
a.Loosen the retaining bolt in the order of
both sides first
and middle.
b.As shown in the figure, tap in a special
tool between
the oil pan and the cylinder block.
c.Tap the side of the special tool and move the tool along the oil pan/cylinder block sealing face,
then remove the oil pan.
Note:
■ Be careful not to damage mating surfaces.
3
）
Remove engine oil suction filter
■Bolts’ tightening torque: (8.4±0.6) N·m
4
）
Remove oil pump housing.
2
、
Inspection after disassembly
1
）
Engine oil suction filter
■Clean the attachment clearly.
2
）
Oil pump housing
■ Check whether all the oil holes on the oil pump are clogged, and clean the holes if it is necessary .
■Check the oil pump housing for cracks or other damage If yes, please replace.
3. Assembly
1
）
Install oil pump housing.
■Ensure the glue coating surface be clean, no oil, dirt, etc
■Apply Dow corning 3-0115 surface sealant or equivalent products. Refer to “oil pump housing
installation”
2
）
Install crankshaft front oil seal
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54
■Place the special tool at the front of the crankshaft and apply engine oil to its periphery.
■Apply the engine oil to the sealing lip,
then push the oil
seal along the guide sleeve by hand until it
touches the
front oil seal housing. Using special tool , tap
it in place.
3）Install the relief valve assembly
4）Install engine oil suction filter.
5）Install oil pan.
■Before installing the oil pan, make sure the cylinder block、sprocket chamber cover、the bottom
end face of the oil seal bracket are clean、 no machine oil、no dirt, etc.
■Remove the remaining sealing glue of the previous process at the three-point joint surface of the
sprocket chamber cover、oil seal bracket and cylinder block, and uniformly apply the new sealing glue
on the joint surface. The diameter of the rubber strip is
4mm.
■Ensure the glue coating surface be clean, no oil, no dirt, etc
■Apply Dow corning 3-0115 surface sealant or equivalent products along the center of glue tank on
flange face of oil pan
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55
■The control method for the amount of glue applied is: the diameter of the glue strip is combined
with its weight, and the diameter is: the diameter of glue strip in zone A is 3mm±0.5mm. The diameter
of glue strip in zone B is 4mm±0.5mm, as shown in the figure below.
■glue strip weight：The glue weight of each oil pan is controlled between 13g to15g.
■Tightening method of oil pan bolts: follow the tightening from the middle to both sides, as shown
in the following sequence.
■First pre-tighten, then retighten to the specified torque：（11±1）N·m。
6）Install oil drain bolts on oil pan
■Bolts’ tightening torque: (39±5) N·m
7）Add engine oil, about 4L.
note:
■Wait at least 30 minutes after installing the oil pan before adding the engine oil
4
、
Inspection after assembly
1
）
Start the engine and make sure there is no oil leakage
2
）
Turn off the engine and wait for 10min,then check whether or not the oil level is between the
upper and lower scale. If the oil is insufficient, please add.
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1.4 Engine cooling system
1.4.1 Cooling circuit
1、Cooling principle map
Cooling principle map
1.4.2 Engine Coolant
1. Inspection
1
）
Liquid level inspection
■ When the engine is cooled down, check if the engine coolant level in a range from MIN to
MAX.
■If necessary, adjust the engine coolant
level.
■If the coolant level is too low, check
for leakage.
2
）
Leakage inspection
Apply pressure on the cooling system to
120kPa using
the radiator cap leak detector to check and confirm that the pressure has not decreased If the pressure
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57
drops, check hoses 、 radiators and water pump for leaks. If no external leakage is found, check the
heating core、cylinder block and cylinder cover.
note:
■Do not remove the radiator cap when the engine is hot.Otherwise, high-pressure engine coolant
escaping from the radiator can cause serious burns.
■ Exceeding test pressure may damage the heat sink.
■When engine coolant decreases, add engine coolant to the radiator. If parts are found damaged,
please repair or replace them.
3）Coolant quality inspection
Check the quality of antifreeze liquid, if there is turbidity、deterioration、odor、foaming and other
phenomena, it is necessary to replace the coolant and clean the water channel.
2、Engine coolant replacement
note:
■To avoid burns, do not replace the coolant when the engine temperature is high
■Cover the radiator cap with a thick cloth and unscrew it carefully. Release the pressure inside
the radiator and then completely unscrew the cover.
■Be careful not to spill engine coolant on the drive belt.
1）Discharge the engine coolant
1 Open the radiator drain plug at the bottom of the radiator and open the radiator cap.
2 Check the engine coolant for iron rust and other impurities or discoloration
2）Refill the engine coolant
1 Install the removed tank and radiator drain plug.
note:
■ Be sure to clean the drain plug and install a new o-ring.
2 Confirm that each hose clamp is firmly tightened.
3 Disconnect the warm air outlet hose. Raise the hose as high as possible
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58
4 Fill the radiator and reservoir with coolant to the specified level.Slowly add the engine coolant
so that the air in the system is gradually discharged.
note:
■Use the original JAC engine coolant Refer to “Recommended oil/liquid and Lubricants”
■Reconnect and continue filling engine coolant when engine coolant overflows blower water
outlet hose
5 Install the radiator cover.
6 Warm to open the thermostat.
Make sure the thermostat is open by touching the radiator down pipe to feel if there is any warm
water coming out.
note:
■Check the engine water temperature indicator to avoid overheating
7 Turn off the engine to reduce the temperature.
8 The engine coolant in the tank was added to the MIN to MAX range.
9 install the radiator cap and Repeat ③～⑧more than twice with until the engine coolant level
no longer drops.
10 Run engine check cooling system for leaks.
3）Flush the cooling system
note:
■Be sure to clean the drain plug and install a new o-ring.
1 Disconnect the blower water outlet hose. Raise the hose as high as possible
2 Add engine coolant to the radiator and reservoir and install the radiator cap.
3 Reconnect and continue filling engine coolant when engine coolant overflows warm air outlet
hose
4 Run the engine to preheat to normal working temperature.
5 Speed up the engine speed several times under no-load condition.
6 Turn off the engine and wait for cooling.
7 Drain water from the system. Refer to “Drain engine coolant”
8 Repeat steps ①～⑦ until the radiator begins to drain clear water.
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1.4.3 Water pump
1
、
Disassembly and Assembly
note:
■When removing the pump,Be careful not to spill engine coolant on the drive belt.
■The water pump cannot disintegrate and should be replaced as a whole.
■After installing the pump, connect the hose and fix it with a clamp, then use the radiator cap
leak detector to check for leakage.
1) disassembly
1 Drain engine coolant from the radiator. Refer to “Engine coolant replacement”
2 Loosen the fixing bolt of water pump belt pulley.
■tightening torque: (8.4±0.6) N·m
3 Remove elastic belt
。
4 Remove the fixing bolt of water pump
■tightening torque: (8.4±0.6) N·m
2
）
Inspection after disassembly
■Check the water pump assembly for serious corrosion, water seal leakage or corrosion
■Check for excessive end clearance resulting in poor work.
■Check whether the pump bearing is stuck or has other damage. Please replace it if necessary.
■The water pump is an on-off pump, which does not work under the condition of power-on, and
works under the condition of power-off.
3
）
Assembly
1 Clean water pump sealing surface
2 Install water pump
■Tighten each fixing bolt evenly and alternately.
3 Install water pump belt pulley
4 Install the elastic belt
5 Add the engine coolant
2
、
Inspection after assembly
■use the radiator cap leak detector to check for leakage.
■Start and warm up the engine. Visually check engine coolant for leakage.
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1.4.4 Thermostat assy.
1
、
Disassembly and Assembly
1) disassembly
1 Drain engine coolant from the radiator water drain plug.. Refer to “Engine coolant
replacement”
note:
■Be sure to operate after the engine is cooling.
■Do not let engine coolant splash on the belt.
2 Disconnect the radiator inlet and outlet pipes and short circle pipes on the side of the thermostat
housing
3 Disconnect the wire harness connector of the coolant temperature sensor and the water
temperature attention switch, and the fixing bolt of the fixing bracket of the front and rear oxygen sensor
wire harness connector and remove them.
4 Remove the fixing bolt of the warm air water return pipe and remove the pipe.
5 Remove the fixing bolts of thermostat upper cover and remove the thermostat.
2
）
Inspection after disassembly
1 Thermostat
■Check the throttle valve opening at
normal room
temperature
The opening temperature of the thermostat
：
82
C
（
open start
），
95
C
（
full open
）。
Maximum lift of valve rod
：
≥8mm
The closing temperature of the thermostat
：
>77C
If the measured value exceeds the specified range, please replace the thermostat.
2 thermostat upper cover and thermostat housing
Check for cracks or other damage.
3
）
Assembly
Please note the following items and install in the reverse order of disassembly.
1 Be careful not to spill engine coolant on the engine Use a cloth to dry the engine coolant.
2 Replace the "O" ring of water inlet pipe with the new "O" ring, and then apply the coolant to
the "O" ring so that they can be easily embedded in the water pump and thermostat housing.
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61
note:
■Do not apply engine oil or other oil substances to the “O” ring.
■The water pipe behind the thermostat housing must be securely installed.
3 When installing a thermostat, keep its jump valve in the highest position.
4 If the water temperature sensor is to
be reused, the
specified sealant should be applied to its
threads.
■specified sealant：Tonsan 1243 thread
sealant
2、Inspection after assembly
■use the radiator cap leak detector to check for leakage. Refer to "Leakage Inspection"
■Start and warm up the engine. Visually check engine coolant for leakage.
1.4.5 Water pipe assy.
1. Disassembly
1 Drain engine coolant from water drain plug at the bottom of the radiator Refer to “Engine
coolant replacement”
note:
■Be sure to operate after the engine is cooling.
2 Remove the radiator upper and lower water hose
3 Remove warm water hose and short circle hose.
4 Remove the inlet pipe fixing bolt and remove the water inlet pipe from the back end of the
water pump.
note:
■Before disassembling, disassemble the battery negative terminal first
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62
2. Assembly
Please note the following items and install in the reverse order of disassembly.
1）Firmly insert each hose Install the clamp ring, and the clamp ring will not clamp the boss of the
pipe
2）Replace the "O" ring of water inlet pipe with the new "O" ring, and then apply the coolant to the
"O" ring so that they can be easily embedded in the water pump and thermostat housing.
note:
■Do not apply engine oil or other oil substances to the “O” ring.
■The water pipe behind the thermostat housing and water pump must be securely installed.
3、Inspection after assembly
1）use the radiator cap leak detector to check for leakage.
2）Start and warm up the engine. Visually check engine coolant for leakage.
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1.5 Engine emission control system
1.5.1 Fuel evaporation system
1、System description
Fuel evaporation system map
Fuel evaporation system theory map
The fuel evaporation system is used to reduce hydrocarbon emissions from the fuel system into the
atmosphere. Use activated carbon in EVAP tanks to reduce hydrocarbon emissions. When the engine is
not running or refueling to the tank, the vapors from the sealed tank are guided into the EVAP tank with
activated carbon and stored there. When the engine is running, the fuel vapor in the EVAP carbon tank is
carried into the intake manifold through the clean line. EVAP Carbon canister solenoid valve is controlled
by ECM. When the engine is working, the steam flow controlled by the EVAP carbon tank solenoid valve
is adjusted proportionally to the increase of air flow.
Air filter
Air inlet manifold
Tank
EVA Carbon
canister
EVAP Carbon canister
solenoid valve
air
Fuel
steam
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64
2、Component inspection
1）EVAP Carbon canister solenoid valve
Steam by-pass line opening of EVAP Carbon canister solenoid valve controls airflow rate.
According to the signal sent by ECM, the EVAP carbon canister solenoid valve repeatedly opens/closes
(ON/OFF), and the valve opening changes to achieve the best engine control. The optimal value stored in
the ECM is determined by the different states of the engine. When the engine is running, the airflow rate
of fuel steam from EVAP carbon canister is adjusted with the change of air flow.
1 Component Description
The EVAP carbon canister solenoid valve uses the ON/OFF duty ratio to control the flow rate of fuel
steam out of the EVAP carbon canister. The EVAP carbon canister solenoid valve is driven by an open
/OFF (ON/OFF) duty ratio signal sent from the ECM. The longer width of the (ON) pulse, the more fuel
vapor will flow through the valve.
2 disassembly
a.Disconnect the vacuum hose of the EVAP carbon canister solenoid valve.
b. Disconnect the wire harness connector of the EVAP carbon canister solenoid valve.
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65
c.Take down the EVAP carbon canister solenoid valve from air inlet manifold bracket.
3) Oil filler cover
a vacuum relief valve is installed on oil filler cover When the pressure in the fuel tank is high
(more fuel vapor), the vacuum relief valve is closed to prevent the fuel vapor from escaping into the
atmosphere. When the pressure in the fuel tank is low (negative pressure), the vacuum relief valve opens
to allow the outside air to enter the fuel tank.
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66
1.5.2 Crankshaft box force ventilation system
1
、
System instruction
Crankshaft box force ventilation system map
1-Air filter 2-air inlet hose3-throttle valve body 4-purification can 5-PCV valve
6-PCV valve connecting hose7-air inlet manifold 8-injector
The crankcase forced ventilation system is designed to send the cylinder air back to air inlet
manifold
The crankcase forced ventilation valve(PCV) is designed to send the cylinder air back to air inlet
manifold When the throttle of the engine is partially opened, the air inlet manifold is sucked into
crankshaft box air through the PCV valve. Normally, the PCV valve has enough air volume to fully
inhale the crankshaft box air and a small amount of ventilation air. ventilation air is drawn into the
crankshaft box from the air inlet pipe In this process, the air passes through a hose that connects air inlet
pipe to the rocker chamber cover. When the throttle of the engine is fully opened, The vacuum of the air
inlet manifold is not sufficient to open the PCV valve and inhale the crankshaft box air. The air will flow
in the opposite direction through the connecting hose. The PCV valve cannot meet the requirements in a
vehicle with a particularly severe gas leakage. because in any case a portion of the gas will pass through
the hose to the air inlet pipe.
2、Component inspection
PCV（Crankshaft box force ventilation ）valve inspection as follow：
1) Working principle:
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67
PCV valve working principle table
Engine working conditions
out of action
Engine working conditions
Idle or decelerate
PCV valve
does not work
PCV valve
Fully open
vacuum degree change
limit
vacuum degree change
Slightly
Engine working conditions
Working
normally
Engine working conditions
Acceleration and
high speed
abnormal
PCV valve
Working
normally
PCV valve
Working slowly
vacuum degree change
large amplitude
vacuum degree change
very large
2. Disassembly
1 Disconnect the PCV valve connecting hose to the cylinder cover guard.
2 Remove the PCV valve from the cylinder cover guard side.
Inspection after disassembly
1 PCV valve
A normal working valve makes a hissing noise when airflow passes. When your finger is at the
vacuum is
moderate
cylinder head guard
no vacuum
cylinder head guard
no
vacuum
cylinder head guard
High
vacuum
cylinder head guard
Engine Maintenance Manual Engine machinery
68
entrance of the valve, you immediately feel a strong vacuum pressure.
2 PCV valve connection hose
a.Check hoses and hose connections for leaks
b.Disconnect all hoses and clean with compressed air. If the plug in the hose cannot be removed,
replace it.
4) Assembly
1 Install PCV valve
■Tightening torque is about 4N, cannot be too big
2 Install hose
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69
Chapter 2 Engine Electric Appliance
2.1 Ignition system
2.1.1 Ignition coil
1
．
element
2．Disassembly and Assembly
1）Disassembly
Note:Confirm that the start switch has been on OFF position.
1 Remove the engine intake manifold.
2 Disconnect the connection between the wire harness connector and the high voltage ignition
coil from the ignition coil .
3 Remove high pressure ignition coil bolts and remove high pressure ignition coil
■Bolts’ tightening torque: (8±2) N·m
4 Use spark plug sleeve to remove spark plug
Fastening torque:25~30N·m
Note: do not drop or shake spark plugs
2）Check after disassembly
1 high pressure ignition coil
■Check the primary coil resistance between the terminal, the primary coil resistance: 0.77 ～
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70
0.95Ω
2 spark plug
Check spark plug.
a. Check whether or not the thread or insulator of the spark plug is damaged or broken
b. Check the spark plug for carbon deposits, oil or oil deposits. Normal spark plug porcelain heads
are between white and yellowish、gray or brown
c. Check if the spark plug electrode is damage.
d. Check spark plug clearance with a plug gauge. Standard clearance: 0.7-0.8mm
e. Check arcing ability of spark plug.
Remove the spark plug and put it on the cylinder cover. Connect the high-voltage wire to the spark
plug terminal for arcing test. Peaking and blue light from spark plugs indicates that they work well.On
the contrary, it indicates that the spark plug is not working well.
3
）
Assembly
Follow the opposite sequence of the demounting sequence.
2.1.2 common fault diagnosis
Fault phenomena
possible causes
solution
Engine can not be started
or starts hard
Ignition coil or switch fault
Check or replace ignition coil or
switch fault
spark plug fault
Check and replace spark plug
The high-voltage line is
disconnected or not connected
Check high voltage line
Engine idling unstable
High pressure wire or spark
plug malfunction
Check High pressure wire or
check and replace spark plug
ignition coil malfunction
Check or replace ignition coil
The engine is wheezing or
weak in acceleration
high voltage line malfunction
Check or replace high voltage line
spark plug fault
Check and replace spark plug
fuel economy is poor
spark plug fault
Check and replace spark plug
2.1.3 Maintenance parameters
ignition coil
primary coil resistance
0.77
～
0.95Ω
spark plug
sparking plug gap
0.7
～
0.8mm
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71
2.2 Starting and Charging System
2.2.1 Storage Battery
1.Prevent battery over-discharge method:
1) Keep the battery surface (especially the top) clean and dry at all times.
2) The connection part of the port should be cleaned and tightened
3) If the car is not in use for a long time, the negative terminal of the battery should be
disconnected.
4) Check the charging status of the battery
2.Check
1) Visual inspection: check whether the battery terminal is damaged, whether the electrolyte is
leaking, if any, please replace it.
2) Voltage Inspection:
① U>13.2V，Please check the electrical system
② 12.5V<U<12.9V，system is normal。
③ 11V<U<12.4V，Please check the charging system.
④ U<11V indicates that the battery is damaged or the charging system is out of order。Please check
the charging system and the battery.
3.Disassembly and Assembly
1) disassembly
■The ignition switch should be switched to the "OFF" position.
① Disconnect the negative terminal.
② Remove the battery positive terminal, the battery pressure plate fixing bolt, take out the pressure
plate
③Take down storage battery
④ Take down the battery tray.
2）Inspection after disassembly
① the battery tray.
■Check for corrosion Please clean it with clean hot water.
② Battery wire harness
■Check for wear and tear or damage. If yes, please replace.
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3）Assembly
Install in reverse order of removal.
Attention
：
■When connecting, the positive terminal of the battery should be connected first.
■After installation, mineral oil can be applied to each terminal post.
2.2.3 Charging System
1. System description
the generator provide the direct current to the vehicle electric system and keep the charging state of
the battery. The output of the voltage is controlled by IC regulator.
When the ignition switch is connected, the current flows into magnet exciting coil, the magnet
exciting coil is initially stimulated. After the generator is started, and when the stator coil begins to
generate, the magnet exciting coil outputs the current stimulation through the stator coil. Terminal B
provides the electricity to the vehicle electric system, and provide the charging power supply to the
battery. IC regulator checks the input voltage at the S terminal, and control the output voltage through this.
If the exciting current enlarges, the output power of the alternating generator also enlarges, if the exciting
current decreases, the output power of the alternating generator also decreases. When the battery voltage
(the voltage of the alternating generator S terminal) reaches about 14.4V adjusting voltage, the exciting
current is cut down. When the battery voltage decreases under the regulating voltage, the voltage
regulator adjusts the output voltage through controlling the exciting current to keep it the constant level.
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1.W-engine speed line 2.IG-Excitation line 3.L-to indicator light 4.S-Signal output terminal
5.B+—Connected generator battery
2. Charging attention lamp
1）When the ignition switch opens and the engine does not start
the power supply goes through the inner fuse box to instrument charging indicator lamp terminal to
instrument terminal, through the generator L terminal to E terminal grounding, the charging indicator
lamp will light on in this time.
2）After starting the engine
when the generator can generate normally, the power supply terminal of the charging indicator lamp
is close to the voltage of the L terminal, the charging indicator lamp lights off. If the charging indicator
lamp still lights on when the engine runs, it means that there is some faults.
If the generator produces no voltage or over-high voltage in working, the indication function of the IC
regulator will open and light on the charging indicator lamp.
3.Disassembly and Assembly
1) disassembly
① Disconnect the battery negative terminal.
② Disconnect the generator harness connector.
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③Loosen the generator adjusting nut and generator supporting nut, and then use the adjusting bolt
to adjust the tensioning degree.
■Tighten torque: generator adjusting nut 20~35N·m
generator supporting nut：（47±5）N·m
④ Remove the Generator belt
⑤Remove the generator from the vehicle
2
）
Assembly
■Install in reverse order of removal.
■Install generator，Check belt tensioning force.
"B" terminal nut tightening torque 10 ~ 12N · m
4. Common faults of charging system
■No electricity generating
■Generator charging indicator light is always on
■voltage is too low
■Voltage is too high
■The generation voltage is unstable
■Abnormal sound
■Generator electric leakage
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5.Charging system inspection process
note:
■If the charging system fails but the test result is normal, check the "B" port connection (check
the tightening torque and voltage drop).
Check items as follow:
1. the lamp bulb
2. the lamp fuse
Ignition switch ON
Charging
attention lamp
goes out
Disconnect the joint
and ground the L side
wire
Charging attention
lamp lights
Charging
attention lamp
goes out
Charging attention
lamp lights
Check items as
follow:
1. Rotor
2. Rotor ring
3. brush
damaged IC regulator,
replace
►Engine starts,
rotation speed is
1500 rpm
Charging
attention lamp
Check items as
follow:
1.drive belt
2. Generator
3. generator S port
4. joint connection
Engine idling
Charging
attention lamp
Normal
Charging attention
lamp lights
Charging attention
lamp goes out
Normal
Engine rotation
speed is 2200
rpm,Measure the
voltage at port B
more than 16.0V
damaged IC
regulator,replace
less than 13.0V
Check items as follow:
1.rotor
2.Rotor sliding ring
3.brush
4.stator
damaged IC
regulator or diode
assembly, replace
Attention lamp: the "charge" attention lamp in the
combination instrument
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Chapter 3 Engine Electronic Control System
3.1 Attentions
3.1.1 Common maintenance precautions
All the failures in electronic control system sensors, actuators, control circuits, ECM and other
components will have some impact on the operation of the engine. Because the ECM has fault
self-diagnostic capabilities, the computer tester can be connected to the ECM for troubleshooting to
identify the cause of the fault in the electronic control system by reading the fault code or data flow.
In order to improve the reliability of the engine electronic control system work, most of the system
components are structurally designed to be sealed, indecomposable, damaged and can not be repaired.
The main task of electronic control system maintenance is to find faulty parts of the system, and replace
the faulty parts.
When servicing the electronic control system, the following precautions must be taken to avoid
damage to the ECM or control components.
1. Only the use of automotive diagnostic tools can be taken to check the electronic control system
(such as digital multimeter, automotive oscilloscope and car diagnostic, etc.).
2. Please use genuine JAC parts in maintenance operations, otherwise it can not guarantee the
normal work of the system.
3. Only unleaded gasoline can be used during maintenance and use.
4. Please follow the standard maintenance diagnosis process for maintenance operations.
5. It is prohibited to operate the disassembly work on the system in the maintenance process.
6. You must be very careful to pick and place electronic components (electronic control module,
sensors, etc.) and do not let it fall.
7. Establish awareness of environmental protection, and effectively handle the waste generated
during the maintenance process.
8. Do not remove or plug in the ECM's harness plug when the ignition switch is on, to prevent the
inductive components in the electronic control system from generating induced voltage during the
power-off or power-on instant, causing damage to the ECM.
9. The ECM harness connector should be securely connected, or the ECM may be damaged.
10. When dismantling the battery or use an external battery across the start, you must first turn off the
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ignition switch, and then you can make the folded or cross-connect operation. Pay special attention to the
battery that can not be connected reversed.
11. When the battery connector is not tightened, never start the engine. Also do not remove the
battery cable while the engine is running. Otherwise it will make the engine charging voltage too large,
damaging the electronic control system components.
12. When turning the engine to check the cylinder compression pressure, please cut off the injector
power or unplug all the injector harness connector to prevent the fuel injected into the exhaust without
examination, resulting in three-way catalytic converter damage.
13 . When the ignition system is inspected , the spark detection shall be carried out only if necessary ,
and the time shall be as short as possible , otherwise a large amount of unburned gasoline will enter the
exhaust pipe and damage the three-way catalyst converter.
14. Do not allow the ECU temperature to exceed 80 ° C while performing thermal condition
simulations of faults and other maintenance operations that may raise the temperature.
15. Removal of tubing and replacement of fuel filters should be carried out by professional
maintenance personnel in well-ventilated areas.
16. Prohibit the use of piercing wire skin to detect the input and output components of the electrical
signal.
3.1.2 Diagnostic tool
■Tool name: electrospray system diagnostic instrument
Functions: read/clear the fault code of the electrical spraying system, observe the data flow, test the
action of parts, etc.
■Tool name: digital multimeter
Function: check the voltage, current, resistance and other characteristic parameters in the electrospray
system.
3.1.3 Engine OBD System Cautions
The Electronic Control Module (ECM) comes with an on-board diagnostic system that lights up
when there is malfunction caused by the aging exhaust system.
■ Before performing any repair or inspection work, please turn the ignition switch OFF and
disconnect the battery negative terminal. Open or short circuits in associated switches, sensors, and
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solenoid valves will cause the fault indicator to light up.
■ After work, be sure to connect and reliably lock the connector. Loose (unlocked) connectors may
open the circuit and cause the fault indicator to light. (Make sure no dirt such as water, grease and other
dirt on the connector, and the connector pins are without bending, fracture, etc.)
■ After work, be sure to arrange and fix the harnesses correctly. If the bracket interferes with the
harness, it may cause a short circuit , causing the fault lamp to light up.
■After work, make sure the rubber hose is connected If the rubber hose is not connected properly,
the failure indicator light may be turned on due to the failure of EVAP system and fuel injection system.
■ Before returning the vehicle to the customer, be sure to clear the useless fault information in the
ECM (repair has been completed).
■ Be sure to use a 12V battery as the power source.
■Do not disconnect the battery while the engine is
running.
■ Before connecting or disconnecting the ECM harness
connector, turn the ignition switch to the "OFF" position and
disconnect the negative battery terminal. Or it may damage
the ECM because the battery is still energizing the ECM even
when the ignition switch is turned "OFF".
■ Before removing the parts, turn the ignition switch
OFF and disconnect the negative battery terminal.
■ Do not disassemble the ECM.
■If a battery cable is disconnected, the memory is
returned to the ECM initial value. ECM will begin to control
itself based on the initial value When the battery port is
disconnected, the running of the engine will change slightly.
But that does not mean there is a failure. Don't change parts for minor changes
■ When connecting the ECM harness connector, push the lever to the bottom to lock the ECM
securely.
■ When inserting the pin connector into the ECU or removing it from the ECU, be careful not to
damage the pin port (bend or broken). When connecting the pin connector, make sure the ECM pin port is
not bent or broken.
Battery
Bend
Crack
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79
■ Securely connect the ECM harness connector. Poor connection can cause very high (ripple) voltage
on the coil and capacitor, causing damage to the ECU.
■ Keep the engine electronic control system components and harness dry.
■ Even a small leak in the air intake system can cause serious malfunctions, so do not easily replace
the air intake pressure sensor.
■ Do not shake the camshaft position sensor (phase) or crankshaft position sensor(location).
■ When measuring the ECM with a circuit tester, do not contact the two gauges together the probe is
inadvertently touched, resulting in a short circuit and damage to the ECM power transistor.
■When measuring the input/output voltage, do not use the ECM grounding port. Otherwise, the
transistor of ECM may be damaged. Grounding except the ECM port should be used;
■Do not use the fuel pump when there is no fuel in the fuel pipe;
■Tighten the fuel hose clamp to the specified torque
■ Do not step on the accelerator pedal during start-up.
■ Do not immediately increase the engine speed after starting.
■Do not accelerate before closing the engine
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3.2 Structure Principle and Maintenance of the Engine Control System
3.2.1 System description
1-carbon canister 2-Carbon canister solenoid valve 3-Electronic throttle valve assembly 4-intake pressure
temperature sensor 5-oil atomizer 6-camshaft position sensor 7-ignition coil 8-Front oxygen sensor 9-three-way
catalyst 10-rear oxygen sensor 11-engine coolant temperature sensor 12-crankshaft position sensor 13- fuel filter
14-electric fuel pump 15-fuel tank 16-diagnose interface 17-ECM
The picture shows the control system diagram, such as sensor location and physical discrepancies,
please prevail in kind.
3.2.2 Electronic control system components
1.fuel injection system
the timing and width of the fuel injection are controlled to provide the best air/fuel mix ratio for the
engine, which is suitable for changing engine operating conditions. Oil injectors are installed at the inlet
of each cylinder Fuel is pumped out of the fuel tank by the fuel pump and distributed to each injector
Under normal circumstances, it will spray fuel to each cylinder every two revolutions of the crankshaft.
he working order of each cylinder is 1-3-4-2.
2.Ignition control system
ECU control diagram
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The ignition system consists of ignition switch, ECU and ignition coil,
The sensors related to ignition control include crankshaft position sensor, inlet temperature and
pressure sensor,
water temperature sensor, throttle position sensor and so on.
The main function of the ignition system is to control working of ignition coil, thus to control
ignition advance angle of engine, which is one of the main control functions of the engine electronic
control system. According to the engine speed, throttle opening, coolant temperature, inlet temperature
pressure, knock sensor and other operating conditions measured by various sensors, ECU calculates and
selects the ignition angle which is most suitable for the current working condition, which make it have
high fuel economy and power performance, reduce emission pollution and prevent deflagration.
The ignition advance angle is determined and controlled by ECU according to the signals of
various sensors.
Closing angle is the angle that the crankshaft or camshaft turns on during the current conduction of
the ignition coil. Closing angle control also known as ignition coil electrification time control. For
inductive energy storage type ignition system, the induction voltage produced by the ignition coil
depends on the current of the primary coil passing through the coil at the moment of breaking. The
higher the current value of the primary coil, the higher the inductive voltage of the ignition coil. Because
of the inductive effect of the coil, under the condition of constant supply voltage, the current flowing
through the coil increases exponentially at the beginning of the primary coil conduction, and it takes a
certain time before the saturation current can be reached. When the closing angle remains constant, the
time of primary current conduction will decrease with the increase of engine speed. In order to meet the
requirements of ignition voltage and ignition energy of gasoline engine, the closing angle of ignition
system is automatically controlled by ECM according to engine speed. When engine speed increases, the
closing angle will be increased appropriately to ensure that the primary coil has enough conduction time,
so that the current of the primary coil can reach or approach the saturation current at the moment of
disconnection, rising the inductive voltage. On the contrary, when engine speed is reduced, ECM will
properly reduce the closing angle, so as to prevent the primary coil from overheating and excessive
power consumption due to the excessive conduction time of the primary coil current.
3.Air intake control system
Air intake system consists of air filter, throttle valve, intake manifold and related pipe.
Air intake control system is to achieve idle control, variable valve control, electronic throttle
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control, turbocharger control and other tasks through the control of air intake,
so as to improve the stability of engine idling operation, or improve engine power, reduce fuel
consumption and emission pollution.
Idle speed control: the electronic control system has the function of automatic control of engine
idling speed. Through engine working temperature, load and other factors measured by various sensors,
to determine the optimal idle speed. And through electronic throttle, the intake amount of idle speed
when automatically controlled idling, achieve the purpose of controlling idling speed. So that the engine
has stable idle speed under various conditions, to prevent idle speed instability or stall, and as far as
possible to reduce idle fuel consumption and emissions pollution.
Electronic throttle control: in the engine with electronic throttle valve, ECU measures operating
condition of accelerator pedal according to various sensors, also calculates and confirms optimum
opening degree of throttle valve according to engine speed, vehicle speed and other factors, control
opening degree of throttle valve by electronic throttle valve actuator, and ensure the best fuel economy
and improve safety and comfort. In addition, the electronic control system of gasoline engine can realize
traction control and cruise control through electronic throttle valve.
Variable valve control: in engine with variable valve, ECU calculates and confirms the optimal
phase of valve distribution according to operating conditions measured by various sensors. Through
timing control of solenoid valve and other actuators, change opening and closing time of intake and
exhaust valve, so that the phase of engine valve and valve overlap angle change with the change of
engine speed and load, and keep the best at all times. Thus, the engine has good fuel economy, power
performance and running stability at any speed and load, and reduces emission pollution.
4.Emission control system
The post-treatment of exhaust in three-way catalytic converters is an effective way to reduce the
concentration of harmful substances in the exhaust gas. Ternary catalytic converters can reduce
hydrocarbon (HC), carbon monoxide (CO) and nitrogen oxides (NOx) by 98% or more, and convert
them into water (H2O), carbon dioxide (CO2) and nitrogen (N2). However, such high efficiency can
only be achieved within a narrow range of the engine's excess air coefficient
=1，
and the goal of
closed-loop control is to ensure that the mixture concentration is within this range. The closed-loop
control system can only act with oxygen sensors The oxygen sensor at the side of the three-element
catalytic converter monitors the oxygen content in the exhaust gas，The dilute mixture（

1）generates
a sensor voltage of about 100mV，The thick mixture（
1）generates about 900mV sensor voltage。
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when
=1，The sensor voltage has a jump。
Closed-loop control responds to input signals（

1=Mixed
gas is too thin1=Mixed gas is too thick)Modify the control variable to produce a correction factor as a
multiplier to modify the duration of the injection.
5.Crankshaft ventilation system
The function of fuel vapor recovery device is to recover the gasoline vapor from the gasoline tank
of vehicle to engine intake pipe,
so that it can burn into the engine cylinder with the fresh mixture, and prevent gasoline vapor from being
discharged into the atmosphere to pollute the environment.
The fuel vapor recovery unit consists of activated carbon canister, solenoid valve, one-way valve
and corresponding steam pipe and vacuum hose.
3.2.3 Vehicle diagnostic system
1.Instruction
On-board Diagnostic system (OBD) is a diagnosis system integrated in engine control system
which can monitor the fault parts and the main function state of engine which affect the exhaust gas
emission. It has the function of identifying, storing and displaying fault information through the
self-diagnostic malfunction indicator light (MIL).
2.function introduction
The main functions of the diagnostic system are monitoring functions, memory fault codes and
warning functions, fail-safe functions
and data output functions.
（
1
）
Monitoring function
The target of the diagnosis system monitoring is the various sensors in the engine electronic control
system, actuator
and the control process of the electronic control system. The fault self-diagnosis system continuously
monitors the signal of the electronic control system during the running of the vehicle, when a signal
exceeds the preset range value, and the phenomenon does not disappear in a certain period of time. The
fault self-diagnosis system determines that the corresponding circuit or component of the signal has
failed.
（
2
）
Store fault code and warning function. Once the fault self-diagnosis system detects a fault in
the electronic control system, it immediately lights the fault warning light above the dashboard to
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remind the driver to promptly send the vehicle to the repair shop for inspection and maintenance, so as
to avoid any further damage.
The fault self-diagnosis system also detects that the fault is stored
in the memory of the ECM as a fault code. During maintenance, the inspector can read out the fault code
stored in the ECM by using a certain method to provide an accurate basis for finding the fault location.
（
3
）
Failure protection function According to the different monitoring object, the fault
self-diagnosis system will take different failure protection measures when finding fault.
（
4
）
Data storage output function. The cells that store data in ECU are ROM and RAM,
respectively, memory ROM stored in the program is based on accurate calculation and a large number of
experimental data, the inherent program in the engine work, constantly with the acquisition of the
signals of each sensor to compare and calculate, to achieve the control of the engine.
In the automotive electronic control system circuit has a dedicated diagnostic socket, as long as the
car ECM decoder and this diagnostic socket connection,
you can access the automotive ECM storage unit, read out the stored fault code.
In addition, the fault self-diagnosis system can also output the data flow reflecting the working
condition of the automobile electronic control system by diagnosing the outlet outward.
3.Fault light description and control strategy
1）Engine fault indicator light (MIL)：instructions required for emissions-related components or
system failures, MIL is generally a light that can be displayed on the dashboard in compliance with
regulatory standards.
2 The activation of the Mil led follows the following principles:
1 Ignition switch is in the "ON" state (non-start), MIL continues to light.
2 3 seconds after the engine starts, if there is no fault request in the fault memory to turn on the
MIL, the MIL goes off.
3 There is a fault in the memory required to light the MIL request, or outside the ECM has a
MIL request, MIL are lit.
4 When there is a flashing MIL request outside the ECM, or there is a blinking MIL request due
to a fire or there is a fault request in the memory that flashes MIL, the MIL flashes at 1Hz.
4. Troubleshooting steps
1) For vehicles with OBD function, troubleshooting is generally followed by the following steps:
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OBD Troubleshooting Steps Table
1. Connect the diagnostic test equipment to
the diagnostic connector and switch on the
diagnostic test equipment.
2. Connect the ignition switch.
3. Read fault related information (fault code,
frozen frame, etc.); check workshop manual to
confirm fault parts and types; making maintenance
plan according to fault related information and
experience.
4. Troubleshooting.
5. To clear the fault memory, the proper
operation of the vehicle and the operation mode
must meet the conditions of the corresponding fault
diagnosis; Read the fault information to confirm
that the fault has been excluded.
2
）
Fault diagnosis common detection and diagnostic equipment
Compared with the mechanical system, the automobile electronic control system has a
fundamentally different overhaul mode. It is necessary to rely on the electronic equipment and use the
information of the self-diagnosis system to diagnose the fault. The common equipment for overhaul of
electronic control system includes automobile computer tester and digital multimeter.
Connect the data cable of the computer detector to the diagnostic outlet on the car to connect with
the automotive ECM, accessing to the ECM memory of the fault diagnosis data, including fault code,
data flow and so on, so as to understand the auto fault diagnosis system monitoring results and the work
of the electronic control system, to provide a basis for quick troubleshooting. In addition, it can carry out
the action test and so on.
（
1
）
Read and Clear fault codes
By connecting the car's computer detector with the fault diagnosis seat on the car, it is easy to read
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the fault code stored in the ECM. The car's computer diagnostic device displays both the fault and its
meaning on the screen By reading the fault codes, maintenance personnel can find out the short circuit,
open circuit and other faults of most sensors and their control circuits in the automotive electronic
control system.
After troubleshooting, the computer tester can send instructions to the car electronic control system
to eliminate ECM stored fault code to turn off the the fault warning light.
（
2
）
Read data stream
The car computer tester is connected with the electronic control system to read the running status of
the ECM
and the instantaneous data of various input and output electric signals (such as the signal of each sensor,
the calculation result of the ECM, the control mode, The control signal issued by each actuator, etc.).
Maintenance personnel can judge whether the system is working normally according to the changes of
various data or compare the values of various signals with the standard values under specific working
conditions so as to accurately determine the type and location of the fault.
（
3
）
Action test
The motion test is to issue a work instruction to the ECM of the automotive electronic control
system through the computer tester to drive
or stop the work of some actuators to detect the working condition of the actuator and find the faulty
actuator or control circuit.
3.2.4 Engine fault diagnosis
1、Engine control system troubleshooting overview
If the engine electronic control system components (sensors, ECM, injector, etc.) failure, oil supply
disrupts or it can't provide the correct fuel quantity for engine different working conditions, will produce
the following situations:
a.The engine is difficult to start or cannot start at all
b.Engine idling unstable
c.Poor driving performance
In case of any of the above situations, routine testing including basic engine inspection (ignition
system failure, correct engine adjustment, etc.) shall be conducted first. Then the components of the
engine electronic control system are checked by a fault diagnosis instrument
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MT62.1 Common fault code list of ECU control system
No.
Fault code
Fault code information
1
P 0012
Air inletVCPCamshaft phase error is large
2
P 0015
ExhaustVCPCamshaft phase error is large
3
P 0016
IntakeVCPcamshaft tooth learning deviation exceed range
4
P 0017
ExhaustVCPcamshaft tooth learning deviation exceed range
5
P 0026
intakeVCPhydraulic pressure control valve vised
6
P 0027
ExhaustVCPhydraulic pressure control valve vised
7
P 0031
Front oxygen sensor heater short circuit to low voltage
8
P 0032
Front oxygen sensor heater short circuit to high voltage
9
P 0037
Rear oxygen sensor heater short circuit to low voltage
10
P 0038
Rear oxygen sensor heater short circuit to high voltage
11
P 0068
Electronic throttle valve air flow fault
12
P 0075
intakeVCPhydraulic pressure control valve coil low voltage or open circuit
13
P 0076
intakeVCPhydraulic pressure control valve coil low voltage
14
P 0077
intakeVCPhydraulic pressure control valve coil high voltage
15
P 0078
exhaustVCPhydraulic pressure control valve coil low voltage or open circuit
16
P 0079
exhaustVCPhydraulic pressure control valve coil low voltage
17
P 0080
exhaustVCPhydraulic pressure control valve coil high voltage
18
P 0107
Intake pressure sensor circuit low voltage or open circuit
19
P 0108
Intake pressure sensor circuit high voltage
20
P 0112
Intake temperature sensor circuit low voltage
21
P 0113
Intake temperature sensor circuit high voltage or open circuit
22
P 0117
Coolant temperature sensor circuit low voltage
23
P 0118
Coolant temperature sensor circuit high voltage or open circuit
24
P 0122
Electronic throttle valve position sensor1#circuit low voltage
25
P 0123
Electronic throttle valve position sensor1#circuit high voltage
26
P 0130
Front oxygen sensor open circuit
27
P 0131
Front oxygen sensor short circuit to low voltage
28
P 0132
Front oxygen sensor short circuit to high voltage
29
P 0133
front oxygen sensor responds too slowly
30
P 0134
The front oxygen sensor has too few dense conversion times
31
P 0136
Rear oxygen sensor open circuit
32
P 0137
Rear oxygen sensor short circuit to low voltage
33
P 0138
Rear oxygen sensor short circuit to high voltage
34
P 014C
front oxygen sensor dense thick-thin conversion times is too slowly
35
P 014D
front oxygen sensor dense thin-thick conversion times is too slowly
36
P 0171
Non-idle fuel system is too thin
37
P 0172
Non-idle fuel system is too thick
38
P 0222
Electronic throttle valve position sensor2#circuit low voltage
39
P 0223
Electronic throttle valve position sensor2#circuit high voltage
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88
No.
Fault code
Fault code information
40
P 0230
Fuel pump relay fault
41
P 0261
1
st
cylinder fuel injector circuit low voltage fault
42
P 0262
1
st
cylinder fuel injector circuit high voltage fault
43
P 0264
2
nd
cylinder fuel injector circuit low voltage fault
44
P 0265
2
st
cylinder fuel injector circuit high voltage fault
45
P 0267
3
rd
cylinder fuel injector circuit low voltage fault
46
P 0268
3
st
cylinder fuel injector circuit high voltage fault
47
P 0270
4
th
cylinder fuel injector circuit low voltage fault
48
P 0271
4
st
cylinder fuel injector circuit high voltage fault
49
P 0300
Single cylinder or multi-cylinder miss fire
50
P 0324
Knock control system failure
51
P 0325
Knock sensor failure
52
P 0335
Crankshaft position sensor circuit no signal
53
P 0336
Crankshaft position sensor circuit signal interfere
54
P 0340
Camshaft position sensor line without signal/Intake VCP camshaft position sensor state
diagnosis
55
P 0341
Camshaft position sensor line rationality failure/intakeVCPtarget wheel fault diagnosis
56
P 0351
Ignition coil "A" disconnects (1 cylinder)
57
P 0352
Ignition coil "B" disconnects (3 cylinder)
58
P 0353
Ignition coil "C" disconnects (4 cylinder)
59
P 0354
Ignition coil "D" disconnects (2 cylinder)
60
P 0366
exhaustVCPtarget wheel－CAMsensor fault
61
P 0401
Insufficient EGR flow
62
P 0402
Excessive EGR flow
63
P 0403
EGR control circuit failure
64
P 0404
EGR opening error is big
65
P 0405
EGR sensor lines open or short to low voltage
66
P 0406
EGR short circuit to high voltage
67
P 0420
Catalytic converter is too inefficient
68
P 0458
Carbon canister electromagnetic valve short circuit to low voltage or open circuit
69
P 0459
Carbon canister electromagnetic valve short circuit to high voltage
70
P 0480
Low speed fan failure
71
P 0481
High speed fan failure
72
P 0500
Speed signal source failure (speed signal comes from TCM/ABS/ESP through CAN)
73
P 0504
Brake switch relativity fault
74
P 0506
Idling engine speed too low
75
P 0507
Idling engine speed too high
76
P 0557
Brake power vacuum pressure sensor short-circuit to low voltage or disconnect
77
P 0558
Brake power vacuum pressure sensor short circuit to high voltage
78
P 0562
System voltage is low
79
P 0563
System voltage is high
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No.
Fault code
Fault code information
80
P 0564
Cruise control input line fault
81
P 0565
Cruise“On/Off”signal interference
82
P 0566
Cruise“Cancel”signal interference
83
P 0566
Cruise“Cancel”signal embedded
84
P 0567
Cruise“Resume”signal interference
85
P 0567
Cruise“Resume”signal embedded
86
P 0568
Cruise“Set”signal interference
87
P 0568
Cruise“Set”signal embedded
88
P 0571
The switch state of the brake lamp has not changed during braking
89
P 058A
Battery sensor failure (from LIN)
90
P 0598
Electronic thermostat heating control circuit low voltage
91
P 0599
Electronic thermostat heating control circuit high voltage
92
P 0601
ROM error
93
P 0602
ECM programme error(Software version does not match)
94
P 0606
ECM processor fault
95
P 0606
ECM processor fault
96
P 0606
ECM processor fault
97
P 0606
ECM processor fault
98
P 0606
ECM processor fault
99
P 060A
ECM processor fault
100
P 060A
ECM processor fault
101
P 060A
ECM processor fault
102
P 0616
Starting motor relay circuit high voltage
103
P 0617
Starting motor relay circuit low voltage
104
P 0630
VIN code not written or incorrect
105
P 0633
The alarm failed to learn
106
P 0641
ETC reference voltageA#amplitude
107
P 0646
Air conditioning clutch relay short circuit to low voltage or open circuit
108
P 0647
Air conditioning clutch relay short circuit to high voltage
109
P 0651
ETC reference voltageB#amplitude
110
P 065C
Generator mechanical fault
111
P 065B
Generator electrical failure
112
P 0685
Main relay fault
113
P 0685
Main relay fault
114
P 0831
Low voltage (short connection) of clutch switch circuit
115
P 0832
High voltage of clutch switch circuit (short connection to power or circuit breaker)
116
P 0A3B
The generator is too hot
117
P 1167
Excessive thick when front oxygen decelerating and cutting off fuel
118
P 1171
Excessive thin when front oxygen accelerating and concentrating
119
P 1336
58 tooth gear wheel error not learning
120
P 1404
The EGR valve failed to return to the closed state
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No.
Fault code
Fault code information
121
P 1404
The EGR valve failed to return to the closed state
122
P 1515
The starter state input is disconnected
123
P 1516
ETC drive steady state diagnosis fault
124
P 1561
Transmission chain status inputs short low
125
P 1562
Transmission chain status input short high
126
P 1563
Logic diagnosis drive chain status StuckLow
127
P 1564
Logic diagnosis drive chain status Stuckhigh
128
P 1566
Start/stop main switch Signal bonding
129
P 1567
The battery temperature is too high
130
P 1615
Start the relays open
131
P 1616
start relay bonding
132
P 2101
ETC drive second order diagnosis fault
133
P 2104
Engine forced idling
134
P 2105
Engine forced stop
135
P 2106
Engine function limited
136
P 2110
Engine power management
137
P 2119
Electronic throttle valve return fault
138
P 2122
Electronic accelerator pedal position sensor1#circuit low voltage
139
P 2123
Electronic accelerator pedal position sensor1#circuit high voltage
140
P 2127
Electronic accelerator pedal position sensor2#circuit low voltage
141
P 2128
Electronic accelerator pedal position sensor2#circuit high voltage
142
P 2135
Electronic throttle valve position sensor1#、2#circuit related fault
143
P 2138
Electronic accelerator pedal position sensor1#、2# circuitrelated fault
144
P 2187
idle fuel system is too thin
145
P 2188
idle fuel system is too thick
146
P 2300
Ignition coil "A" shorted to low voltage (1 cylinder)
147
P 2301
Ignition coil "A" shorted to high voltage (1 cylinder)
148
P 2303
Ignition coil "B" shorted to low voltage (3 cylinder)
149
P 2304
Ignition coil "B" shorted to high voltage (3 cylinder)
150
P 2306
Ignition coil "C" shorted to low voltage (4 cylinder)
151
P 2307
Ignition coil "C" shorted to high voltage (4 cylinder)
152
P 2309
Ignition coil "D" shorted to low voltage (2 cylinder)
153
P 2310
Ignition coil "D" shorted to high voltage (2 cylinder)
154
P 2A01
rear oxygen sensor decelerating and breaking response too slowly
155
U 0001
CAN network communication failure(C001)
156
U 0028
LIN communication failure (C028)
157
U 0073
CAN bus close(C073)
158
U 0121
Communication loss between ECU andABScontrol module(C121)
159
U 0126
Communication between ECM and steering Angle sensor is lost(C126)
160
U 012D
Communication loss between ECU and intelligent generator (C12D)
161
U 0131
Communication loss between ECU and power steering control module(C131)
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No.
Fault code
Fault code information
162
U 0140
Communication loss between ECU and car body control module(C140)
163
U 0167
The burglar didn't respond(C167)
164
U 029A
Communication between ECU and battery sensor is lost(C29A)
165
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2.Faults diagnosis flowchart
Inspection Start
3. Confirm symptoms
Try to diagnose the symptoms
described by the customer.
1. Obtain symptom information
Ask the client for details about the symptoms
2.Inspect DTC
Check the DTC, print the DTC
and freeze frame data, and check
the related maintenance records
4. Confirm symptoms
Try to diagnose the symptoms
described by the customer.
5. Execute the DTC confirmation step
6. Perform basic inspections
9. Check the system failure
through the symptom table
7. Run the fault diagnosis
and inspection mode
8. Check the fault parts
10.Check the defective parts by
means of the diagnostic procedure
11. repair or replace faulty parts
12. Final check
Make sure no symptoms are detected
Perform the DTC confirmation step again, and
then make sure the failure is properly repaired
Inspection End.
The client described the
symptoms and the instrument
showed the DTC
The client did
not describe the
symptoms and
the instrument
showed DTC
The client described the
symptoms and the instrument
did not display DTC
Do not use fault diagnostic instrument
Within the range of
technical parameters
No fault components detected
Use fault diagnostic
instrument
Beyond the range of
technical parameters
Fault
Abnormal (DTC detected)
Abnormal (the symptoms
are still there)
Normal
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note:
■Before disassembling and installing any components, read the fault code first and then
disconnect the negative terminal of the battery
。
■Turn off the ignition switch before disconnecting the wiring harness from the battery terminal
。
If the battery wiring harness is disconnected while the engine is working or the ignition switch is
turned on, ECM will be damaged
■The wire harness between the ECM and the sensor shall be shielded by an earth wire connected
to the body to prevent the ignition system interference and radio interference
。
If the shielding harness
fails, the harness must be replaced.
■When checking the charging status of the generator, do not disconnect the positive electrode of
the battery to prevent ECM damage.
■When charging the battery with an external charger, disconnect the battery connection to
prevent damage to ECM
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3.3 Structure Principle and Maintenance of the Engine Electric Components
The electronic components covered in this section mainly include sensors, actuators and ECM. This
section mainly describes the working principle of electronic components, structure, circuits and related
maintenance.
The sensor's basic circuit generally has 3 wirings of power, signal and ground. Some sensors do not
need a power supply, or the power circuit is built into the ECM, so that they only have the signal and
ground two wirings. If they use the shell of iron, there may be only one link to the ECM signal line, so
that the circuit is very simple, and some sensors circuit is very complex. The complexity of the sensor
circuit depends on the type and structure principle of the sensor, the main sensors in the engine
electronic control system are switch type, resistor type, pulse type, voltage type and so on.
Switch-type sensor is a simple structure sensor, usually has two terminals. Its circuit has the
iron-and power-type two, of which the iron-type circuit is the end of the switch to the grounding, and the
power-type circuit switch to the end of the power supply.
Resistive sensor is the most widely used sensor in electronic control system. Its structure has
variable resistor type, potentiometer, etc., generally using the principle of DC circuit partial pressure to
generate electrical signals. In order to ensure the accuracy of the signal, the ECU provides a constant
size of the reference voltage as its operating voltage (generally 5V).
Variable resistance sensor has 2 terminals, generally the iron-type circuits, the end of which is the
signal end, the other end of the iron-end; the potentiometer sensor has 3 terminals, respectively, the
power supply end, signal end, and the iron end. Pulse sensor has a variety of principles and structural
forms, such as the electromagnetic using electromagnetic induction principle, photoelectric using
photoelectric principle, hall-style using Hall-effect, and the magnetic resistance type using principle of
reluctance, etc., the circuit is very complex.
The voltage sensor usually uses the electrochemical principle and the piezoelectric effect to change
the measured parameters into electromotive force. Most voltage sensors do not require operating power.
Electronic control system actuators are mainly solenoid valves, motors, relays, transistor switching
circuits, lights and so on. Actuator circuit is usually relatively simple. It is generally only the power and
ground wiring. The ECM uses ground control for most actuators. The power source for this actuator
comes from the battery and the ground wire to the ECM.
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3.3.1 Air inlet temperature pressure sensor
1.Elements instruction
1）MT62.1 electric injection system adopts velocity density air measurement method to detect the
amount of air entering the engine, so as to control the fuel injection pulse width and accurately control
the engine power output. The sensor is composed of an inlet absolute pressure sensor and an inlet
temperature sensor.
2）The inlet absolute pressure sensor (MAP) is a pressure-sensitive variable resistance. Internal
pressure diaphragm of air inlet pressure sensor and a magnet placed inside the coil heart are linked
together, when the intake pipe inlet pressure change, the diaphragm will drive the core to move, the
output voltage of the sensor is changed, ECU can convert the air intake of the starting motor according to
the output voltage of the sensor, engine based on this signal, refer to other signals for engine fuel injection
quantity control. MAP sensors are also used to measure atmospheric pressure at start-up and allow ECM
to adjust automatically at different altitude under certain conditions. The ECM provides a 5V voltage to
the MAP sensor and receives the voltage from the signal line. The sensor provides a circuit to ground
through its variable resistance. The MAP sensor input signal affects the ECM's control of fuel output and
ignition timing.
3) the inlet temperature sensor is a thermistor with a negative temperature coefficient (NTC).The
resistance decreases with the increase of inlet temperature. The engine ECU monitor the change of inlet
temperature through an internal comparison circuit.
working pressure range：10kPa～115kPa
Working temperature range：-40～125℃
2. Sensor installation position
Install on the intake manifold.
3.Sensor circuit diagram
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Terminal 39: 5v power voltage signal
Terminal 43: manifold pressure sensor signal
Terminal 45: power grounding
Terminal 15: air inlet temperature sensor signal
Working voltage:5±0.1V
4、Installation precautions
■Absolute pressure sensor self-tapping bolts’ tightening torque: (6±0.5) N·m
■Make sure the sensor is fully attached to the intake manifold
■ Prohibit brutal disassembly.
5.Failure phenomenon and judgment
●Symptom: the fuel injection function of the ECM of the engine will be abnormal. If the air
mixture is too rich or too thin, the engine will not run normally or accelerates idly and the exhaust pipe
will emit black smoke and so on.
●General Fault Cause: The internal circuit of the sensor is disconnected, or the dirt accumulates,
and the air inlet pipe leaks that causes the incorrect signal.
●Inspection methods:
1
）
Exterior inspection
Check whether the sensor harness connector is well connected, solid and reliable.
Whether the appearance is good, and confirm that there is no impact marks. Check if the sensor
detection hole is blocked.
2
）
Circuit detection
1 Turn the ignition switch off and unplug the sensor end harness terminal.
2 Turn the ignition switch on and measure the terminals of the sensor harness connector
separately with a digital multimeter.
3 Sensor power supply terminals should be measured as 5V reference voltage. If the voltage
value does not match, it indicates that the control circuit or ECM has faulty, and it should be further
tested.
4 When the sensor terminal is measured, the negative resistance between the battery and the
battery should be less than 3Ω, if abnormal, the ground line should be repaired.
5 If the above check is not normal, turn off the ignition switch, unplug the harness ECM
connector, check the wiring harness between the sensor connector and the ECM connector for the
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existence of disconnection, and the line phenomenon.
3.3.2 Coolant temperature sensor
1.Component Description
Engine coolant temperature sensor detects engine coolant temperature and transmits signal to ECM
for start-up, idling, normal operation, injection timing and fuel injection pulse width control, while
providing water temperature signal to instrument, for instrument water temperature display. It uses a
thermistor with a negative temperature coefficient, whose resistance decreases with temperature. The
ECM determines the temperature of the coolant by the output voltage of the sensor and provides the
engine with the best air-fuel ratio mixture.
2.Installment position
3.Elements Circuit Diagram
Pin A: Output coolant temperature signal
Pin C: Ground
Pin B:Vain
Resistance value (Ω)
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The resistance between A and C varies with temperature
temperature
Standard resistance
（
Ω
）
-10
21371
25
2795
85
283
115
115.7
4.Installation precautions
1 ■ Thread sealing with thread sealant;
2 Tighten torque:20±4N·m；
3 Start and idle the engine, Visually check engine coolant for leakage.
5.Failure phenomenon and judgment
●fault phenomenon: When the water temperature sensor fails, the mixture concentration will be
affected. When the temperature signal sent to ECU by the water temperature sensor is lower than the
actual temperature of the engine, it will lead to excessive mixing gas, exhaust black smoke, hot car
idling instability, etc. when the water temperature signal of water temperature sensor is higher than the
actual engine water temperature, will lead to mixed gas is too thin, cold start difficult, cold car idling
instability and other failures. When the water temperature sensor has a short circuit or break fault, the
fault self-diagnosis circuit of ECM will detect this fault, so that the engine fault attention lamp is on, and
ECM will start the failure protection function.
●General fault reasons: Short circuit, open circuit, the output signal voltage and the standard value
does not meet.
●Inspection methods:
1
）
Exterior inspection
Check whether the sensor wiring harness plugs are connected well, solid and reliable; whether the
sensor installation is loose or off; whether the appearance is good. Make sure there is no impact traces.
2) Circuit detection
1 Turn the ignition switch off and unplug the sensor end harness terminal.
2 Turn the ignition switch on and measure the terminals of the sensor harness connector
separately with a digital multimeter.
3 Sensor power supply terminals should be measured as 5V reference voltage. If the voltage
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99
value does not match, it indicates that the control circuit or ECM has faulty, and it should be further
tested.
4 When the sensor terminal is measured, the negative resistance between the battery and the
battery should be less than 3Ω, if abnormal, the ground line should be repaired.
3
）
Performance Test
Unplug the sensor harness connector and remove the sensor. Place the sensor in water, measure the
resistance between the sensor terminals at different temperatures when heating, if it is not corresponding
to the standard value, the sensor should be replaced.
3.3.3 Electronic throttle valve
1.Elements instruction
Electronic throttle valve assembly is one of the main components of intake control management
system in modern engine management system. It directly controls the total intake of the engine, and then
controls the engine speed and output power.
The electronic throttle valve eliminates the mechanical control mechanism of the mechanically
controlled throttle body. Electronic throttle valve include drive motors, drive gear mechanisms, necessary
mechanical transmission components and more powerful special throttle valve position sensors.
As one of the security guarantees of the system, The system is provided with a double output throttle
valve position sensor, and a throttle valve position sensor increases with the opening of the throttle valve
body. The output voltage signal of another throttle valve position sensor decreases with the increase of
throttle valve opening.
2.Installment position
Install on the intake manifold.
3.Elements Circuit Diagram
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Terminal
number
Function
A
5V power supply
B
Throttle motor control
（
+
）
C
Throttle motor control
（
-
）
D
TPS1 signal
E
TPS2 signal
F
Grounded
●Measuring range of throttle valve position sensor
：
Idle condition PS1 is 6%
～
14%
，
TPS2 is 86%
～
94%
；
Full open condition is TPS1
为
86%
～
94%.
●Throttle valve response time
：
≤100ms
（
full open to close
），
≤150ms
（
full close to open
）
4
、
Installation precautions
■Fastening torque
：
10±1N·m
；
■after re-installation, be sure to self-learning
；
■ Prohibit brutal operation and damage to the shell and related sensors.
5.Failure phenomenon and judgment
Fault phenomenon: Throttle valve failure will cause that the engine idling operation not normal
(such as idle speed too high or too low, idling unstable, idling easily flameout) or engine acceleration is
not normal (such as the acceleration of the engine shaking, acceleration response delay, etc.), sometimes
it can lead to the engine in the process of intermittent jitter and other phenomena.
●Fault cause: The potentiometer in the sensor is open or shorted, the motor can not normally open or
close because of the fault, the throttle valve has too much carbon deposit, and the control function of
ECM is abnormal.
●Inspection methods:
1
）
Exterior inspection
Check whether the sensor wiring harness plugs are connected well, solid and reliable; whether the
sensor installation is loose or off; whether the appearance is good. Make sure there is no impact traces.
Slide valves to check whether the rotation is smooth, with or without catching phenomenon. Check
whether there is too much carbon deposit in throttle valve.
2) Circuit
1 Turn the ignition switch off and unplug the sensor end harness terminal.
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2 Open the ignition switch, measure the position sensor harness wire harness plug terminals with a
digital multimeter;
3 Sensor power supply terminals should be measured as 5V reference voltage. If the voltage value
does not match, it indicates that the control circuit or ECM has faulty, and it should be further tested.
4 When the sensor terminal is measured, it should be the conduction state between the battery and
the battery , if abnormal, the ground line should be repaired.
3
）
Position sensor resistance detection
Sensor resistance can be detected with an electronic multimeter. The detection method is as follows:
1 Turn the ignition switch off and unplug the sensor end harness terminal.
2 Use a multimeter to measure the total resistance of the potentiometer on the sensor harness
socket. If there is short circuit, broken circuit or resistance value does not meet the standard, that means
the potentiometer is faulty.
3 Measure the resistance of the potentiometer sliding contact to the ground terminal. The
resistance should change smoothly with the opening or closing of throttle valve, otherwise the
potentiometer is faulty.
3.3.4 Hall sensor
1.Component Description
The camshaft position sensor and crankshaft position sensor are hall sensors, work with the signal
wheel on the camshaft and crankshaft. The signal wheel corresponds to a specific position of the engine.
ECU uses the sensor's digital voltage signal to determine engine operating conditions and implement
one-to-one control.
2.Installment position
They are respectively installed near the camshaft and crankshaft.
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3.Elements Circuit
A：output B：ground C：power
■Working temperature:-40～150℃
■System input voltage: 5.0v (powered by the controller);
■ Working clearance: 0.1-1.5mm。
4.Installation precautions
■Pay attention to installation clearance;
Standard value:0.5~1.5mm
■Tightening torque:9 ~ 11N · m.
■after re-installation, be sure to self-learning；
5.Failure phenomenon and judgment
●Fault phenomenon：If the hall position sensor is input error signal, it can not inject fuel in order,
which is easy to cause engine flameout, idling instability and acceleration weakness.
●General failure reason：The internal component of the sensor is damaged, or the internal circuit is
broken or short-circuit, unable to generate signals; The external circuit of the sensor is broken or
short-circuited; The installation position of the sensor is not correct, and the gap between the sensor and
Crankshaft position sensor
Camshaft position sensor
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the rotor is too large, resulting in abnormal output signal.
●Inspection methods:
1
）
Exterior inspection
Check whether the sensor harness connector is well connected, solid and reliable. Whether the
distance between the Hall element and the signal wheel meets the standard requirements, whether there
is dirt or iron between them, if so, they should be removed.
2
）
Circuit detect: The hall sensor must be able to produce a signal when the power is in normal
condition, so please check its power circuit and the ground circuit first.
1 Turn the ignition switch off and unplug the sensor end harness terminal.
2 Turn the ignition switch on and measure the terminals of the sensor harness connector
separately with a digital multimeter.
3 Measure the sensor power terminal with 5V reference voltage. If the voltage value does not
match, it indicates that the control circuit or ECM has faulty, and it should be further tested.
4 When the sensor terminal is measured, it should be the conduction state between the battery
and the battery , if abnormal, the ground line should be repaired.
5 If the above check is not normal, turn off the ignition switch, unplug the harness ECM
connector, check the wiring harness between the sensor connector and the ECM connector for the
existence of open circuit.
3.3.5 Oxygen sensor
1.Component Description
The oxygen sensor is used to provide information on whether the fuel injected into the engine
cylinder has excess oxygen after it is completely burnt in the air inhaled. ECU can make use of this
information with infinite loop control of the fuel quantity, has resulted in a three main engine exhaust of
toxic ingredients can get maximum conversion and purification in three-way catalytic converter.
Its sensing component is a ceramic pipe with pores, the outside of the pipe wall is surrounded by
the engine exhaust, and the inside opens to atmosphere. The sensor indirectly calculates the pulse width
of fuel injection according to the difference of oxygen concentration on the inside and outside, and sends
it to the ECU, which controls the injection again. At the same time, the output data of the oxygen sensor
are detected, and the data of the oxygen sensor before and after are compared within the ECU to monitor
whether the work of ternary catalysis was good.
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104
The operating voltage of oxygen sensor fluctuates between 0.1-0.9v, and it should change 5-8 times
in 10 seconds. If the frequency value is lower than this, the sensor is aging and needs to be replaced,it
can not be repaired.
2.Installment position
The front (upstream) oxygen sensor is installed on the exhaust manifold before the three-element
catalytic converter, and the back (downstream) oxygen sensor is installed after the three-element
catalytic converter.
3.Elements Circuit
A
：
signal to ground B
：
signal output C
：
heating end- D
：
heating end+
4.Installation precautions
■Plug the installation hole of oxygen sensor with hairless cotton yarn to prevent sundries or oil and
water from entering the exhaust manifold.
■Tightening torque :35±5N·m
；
■It is forbidden to drop oxygen sensor or collide with hard surface.
■Carbon dioxide, silicone oil, engine oil, lead, paint, or other organic contaminants, which are
released from the engine, are forbidden to pollute the sensor.
■Do not pull the wire when installing.
■Do not knot, pinch, or otherwise damage the sensor harness wire.
■Do not use grease, detergent or other impurities on the connector
5.Failure phenomenon and judgment
●Fault phenomenon: once the oxygen sensor and its connecting line malfunction, it will not only
make the emission exceed the standard, but also worsen the working condition sometimes, cause the idle
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105
speed to be unstable or flameout, exhaust pipe to emit black smoke and so on.
●Common failure reasons: oxygen sensor poisoning, surface area carbon deposit, oxygen sensor
internal circuit breakage, heater failure and so on.
●Inspection methods
1
）
Measure heating resistance of oxygen sensor
Turn ignition switch to “OFF”, disconnect wiring harness connector of oxygen sensor, use
multimeter to measure resistance between C, D terminal of oxygen sensor. The resistance should accord
with standard value（about 9.6Ω）.
2
）
Check voltage of oxygen sensor heater
Turn on the ignition switch and test the heating power supply voltage of the sensor with a
multimeter. The standard value should be 12V.
3
）
Check whether the connection of several wires on the sensor is good, whether there is
short-circuit, open-circuit , etc.
3.3.6 Fuel injector
1.Component Description
Fuel supplied from the fuel pump is stored and distributed through the oil pressure guide rail
assembly, It provides a stable pressure environment for the fuel system, for the fuel system to provide a
relatively stable pressure environment, make each cylinder oil pressure and oil balance, smooth engine
operation. The fuel injector sprays the fuel according to the signal sent by ECM, and the amount of fuel
injection is determined through the opening time of the solenoid valve of the injector.
2.Installment position
Installed on the fuel rail.
■Standard resistance between two terminals：11~16Ω
3.Installation precautions
■The installation of the oil injector is done by hand. It is forbidden to hit the oil injector with
hammer or other tools.
■When disassembling and reinstalling the injector, the o-ring must be replaced and the sealing
surface of the injector must not be damaged;
■After disassembly, the injector seat should be cleaned to avoid pollution.
4.Failure phenomenon and judgment
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106
■ fault phenomenon: engine power down, idling shaking, starting difficult or even no start. The
engine is high in fuel consumption and will emit black smoke when serious
●General fault reason：The carbon deposits of the fuel injector result in leakage or poor injection
conditions, and the solenoid coil is damaged and cannot work. The injector leaks oil.
●Inspection methods
1
）
Electromagnetic coil detection
The electromagnetic coil resistance is measured with a multimeter, 11 ~ 16 Ω resistance.
2
）
Exterior inspection
Check whether or not the fuel injector has carbon deposition and other phenomena.
3
）
Control signal detection
Connect the positive and negative poles of the light-emitting diode test lamp to the power line and
the ECM connection line of the fuel injector respectively. When the engine is running, the light-emitting
diode test lamp should be shining. If it is not shining, it indicates that the control circuit of the fuel
injector is malfunctioning, and the control circuit should be further overhauled. If there is an electric
pulse in the control circuit during measurement but the injector does not spray oil, that means the
injector is faulty.
4
）
Control circuit detection
1 Turn on the ignition switch and unplug the fuel injector wire bundle. The power ends supply
voltage should be 12V.Otherwise, it indicates that the power circuit of the fuel injector is broken, and it
should further check whether or not the power fuse is burnt out 、the main relay of the electric control
system of the engine is faulty.
2 If the fuel injector does not spray oil under the normal condition of the power circuit, check
whether the line from the fuel injector to ECM is broken. When checking, the ignition switch should be
closed first, the wire bundle plugs of each fuel injector should be removed, and the circuit between each
fuel injector and ECM should be measured with a multimeter according to the circuit diagram.
3
3.3.7 Knock sensor
1.Component Description
2.The knock sensor is installed on the side of the cylinder block, generally between 2 and 3
cylinders, which is conducive to the engine detonation balance, The ECU uses the vibration frequency
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107
signal outputted by the detonation sensor to filter through the internal ECU, so as to judge whether the
engine has a knock or not. When the knock signal is detected, the ECU gradually reduces the ignition
advance Angle until no knock occurs, and then gradually recovers until the knock edge, so repeatedly.
Installment position
installed on the side of the cylinder block, generally between 2 、3 cylinders.
3.Elements Circuit Diagram(see right)
1 - signal ground terminal
2 - signal output terminal
4.Installation precautions
■Bolts’ tightening torque: (22.5±2.5) N·m
■Do not drop or damage the sensor
。
5. Failure phenomenon and judgment
●fault phenomenon：make noise and reduce engine power.
●General fault reason：The knock sensor is damaged, there are the short circuit、broken circuit、
fastening bolts are not tightened as required.
●Inspection methods
1) Exterior Inspection
Check whether or not the fastening bolts are tightened as required, whether or not there is any
sundries on the sensor and cylinder joint surface.
2) Circuit inspection
Close the ignition switch, unplug the wire harness plug of the knock sensor, and check whether or
not there is short circuit or open circuit between the signal wire and ECM terminals by comparing the
circuit diagram. If abnormal, it should be repaired.
3
）
Performance check
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Disconnect the cord plug of the detonation sensor and tap with a small hammer on the cylinder
body of the detonation sensor attachment, At the same time measure the voltages between the signal
output end and the iron end of the sensor with the millivolt of the digital multimeter. If the voltage is
generated during tapping, that means the sensor is good, otherwise it should be replaced.
3.3.8 Continuously variable CAM phase regulator and control valve
1.Component Description
Continuously variable CAM phase regulator is used to change the timing of the gas distribution
mechanism. It can continuously adjust the phase relationship between camshaft and crankshaft
according to the needs of the control system and realize the control of gas distribution phase.
VVT pressure regulating control valve is a four-way pulse width control solenoid valve that can
move in both directions. The oil flow can be controlled by the axial movement of the plunger valve. The
engine ECU changes the oil flow to both sides of the rotor blade through the duty ratio signal regulated
by pulse width, thus controlling the timing and phase of the CAM relative to the crankshaft.
2.Installation location (see below)
3.Element Parameters
■VCP operating conditions
Items
Value
Input voltage
11.5-18.0V
Average working
current while holding
position
1.0A
Maximum current
In the case of 100% duty ratio, -40ºC,
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15.5v;2.5A
Environment
temperature
-40 to 150ºC
Cover interior
temperature
-40 to 150ºC
Solenoid valve
temperature
-10 to 150ºC
■OCV valve operating conditions
Type
Engine oil pressure control
solenoid valve
Coil resistance
nominal
：
5.6Ω
（
-30 ºC
）
7.0 Ω
（
20 ºC
）
10.6 Ω
（
150 ºC
）
Minimum current required for
full stroke of plunger valve
1A
Input voltage(through the coil)
nominal：13±0.5V
min：11.0V
max：18.0V
Starting response under normal
input voltage
<50ms,temperature<65ºC
Close the response
<50ms,temperature<65ºC
4.Installation precautions
■OCV Bolts’ tightening torque: (6±1) N·m
■During installation, apply a proper amount of lubricating oil on the o-ring of OCV before
installing OCV.
5.Failure phenomenon and judgment
●Fault phenomenon: when the valve timing control system fails, the actual valve timing will not
match the target valve timing of ECM, which will affect its power performance and emission
performance.
●General failure reasons: OCV valve electromagnetic coil open circuit 、short circuit、valve core
clamping stagnation, etc.
●Inspection methods
1）Measure the resistance of solenoid coil of OCV valve
the resistance between the two pins of OCV is measured by multimeter and the resistance is 8Ω.
2）Dynamic check
Power the OCV valve terminal by 12V to check whether or not the slide of the OCV mid-column
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slide valve is stuck.
3.3.9 Carbon canister solenoid valve
1.Component Description
The gasoline vapor produced in the fuel tank is piped into the activated carbon canister, which can
absorb the gasoline molecules in the gasoline vapor. Another outlet hose on the activated carbon canister
is connected to the engine air inlet pipe. The carbon canister solenoid valve in the middle of the hose
controls the opening and breaking of the line When the engine is running, if the solenoid valve opens,
under the action of vacuum suction within the inlet pipe, air enters beneath the canister, pass the
activated carbon from the upper outlet through the hose into the engine inlet pipe,revaporize the gasoline
molecules attached to the surface of the activated carbon, The air is sucked into the engine to burn,
allowing the fuel to be fully used. At the same time, it can restore the adsorption capacity of activated
carbon in the carbon canister, and it will not be invalidated due to too long use.
2.Installment position
Install on air inlet manifold bracket. (see below)
3.Installation precautions
■Avoid water, oil and other liquids entering the valve during maintenance.
■Pay attention to the direction of installation.
4.Failure phenomenon and judgment
●fault phenomenon ： The first is the failure, that is, the fuel vapor in the fuel tank cannot be
recovered, there is a fuel smell in the car during the summer driving; Second, the work is abnormal, such
as when the fuel vapor recovery work in the engine idle speed, results in too much mixture or influence
the engine idle speed stability.
●General fault reason：The solenoid valve is not working normally, it is closed continuously, the
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solenoid valve is often opened, and the solenoid valve is blocked.
●Inspection methods:
1
）
Measure the resistance
the resistance between the two pins of charcoal canister solenoid valve is measured by multimeter
and the resistance is 19~22Ω（20℃）.
2
）
Performance check
Unplug the cable bundle plug of the solenoid valve and blow air into the solenoid valve. The
solenoid valve should not be ventilated. Connect the 12V power supply to the two terminals of the
solenoid valve and blow air into the solenoid valve at the same time. The solenoid valve should be able
to ventilate. If there is any abnormality, it indicates that the solenoid valve is out of order.
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3.3.10 EGR valve
1.Elements instruction
The EGR is built to return a small fraction of the waste from gasoline engines to the cylinder. The
inert gas of recirculating waste gas will delay the burning process and reduce the amount of oxynitride
compounds. Because the change of waste recycling amount may have opposite effects on different
pollution components, it will have a positive effect on emissions.
2.Installment position
3.Installation precautions
■The gasket should be clean during installation to prevent air leakage
■Pay attention to the direction of installation.
4.Elements Circuit
Terminal1--power supply wire
Terminal 2-- grounding
Terminal 3--signal wire
Terminal 4--Solenoid valve+
Terminal 5--Solenoid valve-
5. common fault
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■Difference between EGR valve opening set value and the actual value is higher than the upper
limit (positive deviation is too large)
■EGR valve is stuck in a closed state
■Difference between EGR valve opening set value and the actual value is below the lower limit
(negative deviation is too large)
6.Inspection strategy
A The H - bridge circuit of the EGR valve drived by ECU breaks,EGR valve is stuck in a closed
position
B The H - bridge circuit of the EGR valve drived by ECU has positive or negative
disconnection,EGR valve is stuck in a closed position.
3.3.11 Ignition coil
1. Overview
This engine adopts the independent electric control ignition system, the secondary coil of the
ignition coil is directly connected with the spark plug. In this ignition system, each ignition coil is
Ignition coil
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connected with ECM to calculate the ignition advance angle according to the signals of various sensors,
and the piston positions of each cylinder are measured according to the crankshaft position sensor.
According to the working order of each cylinder, the ignition signal is sent out to each ignition coil in
turn. According to the ignition signal of ECM, the ignition coil of each cylinder controls the conduction
and disconnection of the primary winding current of each ignition coil, so that the secondary high
voltage is generated, which is directly sent to the spark plug for ignition.
The ignition coil consists of two sets of coils, primary coils and secondary coils, the main function
of which is to turn the low voltage of the vehicle into high voltage.
2.Working principle
Ignition coil consists of primary winding resistance, secondary winding and iron core, shell, etc.
When some primary resistance grounding is connected, the primary resistance is charged. Once the
primary resistive circuit is cut off by ECU, the charge is suspended and a high voltage is induced in the
secondary resistance to discharge the spark plug.
3
、
Installment position
Ignition coil is installed on engine cylinder head cover.
4、Installation precautions
Packing, transport and assembly process can not be removed high pressure connecting rod.
Fastening bolt torque: M6 6~10N.m
Be sure to disconnect the battery negative electrode before installation and disassembly
5. Technical parameters and pin definitions
Working voltage: +12V
Primary coil resistance: 0.75Ω
Stitch definition
Engine
-
ECU control
signal
Battery +
High voltage
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Pin 1——Power supply
Pin 2——ECU control signal
Pin 3——Ground
6. Failure phenomenon and diagnosis method
General fault reasons: short circuit or open circuit inside the coil, leakage of the coil, cracks in
the shell, insufficient ignition energy caused by the aging of the coil, and breakdown of the coil;
Fault phenomenon: ignition coil failure causes spark plug no fire or fire weak, cause engine
work difficult to start, can not start or shake.
Inspection methods
When there is a failure of individual cylinders to ignite, the ignition coil can be exchanged to
determine the cause of component damage
or electric has fault. If all cylinders do not ignite, the cause of failure should be in the control circuit,
sensor or ECU, and it is unlikely that all ignition coils will be damaged at the same time. Therefore, as
long as the control circuit is detected, the fault range can be determined.
4）Control circuit detection
Disconnect wire harness plug of the ignition coil, turn on the ignition switch, and the measuring
power supply terminal shall be 12V battery
voltage. If is 0V, indicating that the power circuit failure, should be further overhaul.
Measure grounding terminal of wiring harness connector, resistance between it and negative
electrode of the battery should be less than 3Ω. If abnormal, it should be repaired.
Measure the signal terminal of the wire harness plug with a light emitting diode test lamp. When
starting the engine, the test lights should flicker, otherwise the ECU does not send a ignition signal to the
ignition coil. The crankshaft position sensor may be malfunctioning, or the ECU may not work and
should be further overhauled.
5
）
Performance check
Remove the ignition coil, attach the spark plug and make it grounding. Start the engine and check
whether there is high pressure spark in the spark plug electrode.
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3.3.12 Spark plug
1. Overview
The role of the spark plug is to send the ignition coil to the pulse high voltage discharge, to break
through the air between the two electrodes of the spark plug, and to produce an electric spark to ignite
the mixed gas in the cylinder.
2.Working principle
The main parts of spark plug are insulator, shell, connection screw and electrode. Spark plug
electrode consists of center electrode and side electrode, and the spark gap is between them. The high
voltage current from the ignition coil passes through the central electrode and then discharges at the
bottom end of the discharge gap.
3.Technical characteristics of the parameters
Ignition clearance: 0.7~0.8mm
Spark plug heat value: 6
Resistance value between shell and connecting column: 6±3kΩ
4
、
Installation precautions
During installation, hammers and other tools are prohibited
Spark plug tightening torque: 23 ± 3N.m;
5
、
Failure phenomenon and judgment
General failure reasons: spark plug ablation and so on.
Fault phenomenon: it is difficult to start and shake.
Inspection methods:
Observe color:
Normal working spark plug, its insulator skirt is russet and relatively clean. If the spark plug shows
the following symptoms, it indicates that the engine or spark plug is not working properly.
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4 Spark plug electrode melts and the body is white. This indicates that the high temperature in
the cylinder causes spark plug ablation, which may be due to excessive carbon accumulation in the
cylinder, too small valve clearance, too late ignition time, and too thin and damaged spark plug sealing
ring. The spark plug failed to tighten according to the required torque, engine heat dissipation and so on.
5 Spark plug electrodes become round and insulator scarring. The reason is that the ignition time
is too early, the octane number of gasoline is too low, and the heat value of spark plug is too high.
6 The top of the spark plug insulator is broken. This shows that the engine detonation
combustion, instantaneous high pressure shock wave will break the insulator. The reason is that the
ignition time is too early, the octane number of gasoline is low, the combustion chamber is serious
carbon deposit and the temperature is too high.
7 The top of the spark plug insulator has gray and black stripes. This shows that the spark plug
has cracked and leaked gas.
8 There are oily deposits between the tip of the spark plug insulator and the electrode. This
indicates that the lubricating oil has entered the cylinder to participate in combustion. If only individual
spark plugs have deposits , it is due to failure of single cylinder valve oil seal etc . If all spark plugs have
carbon deposition , a systematic lubrication system and crankcase ventilation device will be considered.
9 There are black deposits between the tip of the spark plug insulator and the electrode. This
indicates that the mixture does not burn well, mainly because the mixture is too dense, leaving the black
soot layer on the spark plug.
10 There are gray deposits between the top of the spark plug insulator and the electrode, which is
usually due to the gasoline quality does not meet the requirements, gasoline additives after combustion
products, this type of sediment will reduce the spark plug ignition performance.
11 The flame-plug insulator skirt and electrode are moist and oily. This means that high voltage
wire of the cylinder has no
power supply or weak electric energy.
3
）
Spark-over test:
Remove the spark plug, install it on the ignition coil, make the shell of the spark plug iron with the
cylinder head, turn on the ignition switch, turn the engine with the starting device, and see if the spark
plug is igniting. Generally speaking, as long as spark plug jump out of the spark is blue white or purple
white, and in the fire at the same time issued a "patter" sound, indicating that the spark plug fire is
stronger.
4
）
Measuring electrode gap:
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The electrode gap of spark plug was measured with thick gauge or circular gauge, the standard
value of 0.7 ~ 0.8 mm.
3.3.13 On-off Water Pump
1. Overview
Compared with ordinary water pumps, the on-off water pump according to the power On and off
the electronic components of the switching water pump controlled by ECU realizes the separation
between the pump pulley and the pump impeller,reduce the cold But fluid flow, in order to achieve the
purpose of rapid warming.
2.Working principle
ECU powers on, the impeller coil is energized, the armature is absorbed by the electromagnetic
force, the torque of the coil spring clutch disappears, and the water pump belt wheel is detached from the
pump impeller. ECU powers off, impeller coil powers off, armature back, coil spring clutch clamping
belt pulley, impeller rotation, the same as ordinary mechanical pumps.
3、Technical characteristics of the parameters
Water pump service environment
：
water temperature
：
-40°C~120°C
environment temperature
：
-40°C~135°C
Working voltage
：
9-16V
the minimum voltage for the clutch breaking away completely
：
9V
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4、Installation precautions
Before installation, check that the gear train turns flexibly without lag
5、Failure phenomenon and judgment
General fault reason:Clutch failure
Faults phenomena:high temperature
Remove the water pump, power off the pump, rotate belt pulley counterclockwise by hand, check
whether the impeller is synchronous to rotating at the same time, if it does not rotate synchronously as
the same in clockwise,that means the pump is damaged.
3.3.14 ECM
ECU is the control center of the electronic control system, this system is DELPHI MT62.1 control
system, its functions mainly are the followings:
1.Receive signals from various sensors to obtain engine operating parameters and provide the basis
for the control of engine systems.
2.According to various operating parameters of engine provided by the sensor, according to the set
program and control strategy, output control signals to fuel injector, ignition coil and other actuators, so
as to realize the control of each engine system.
3.Monitor sensors, control circuits, actuators and other signals of the electronic control system.
When the signal is abnormal, light up the fault warning lamp to issue an alarm in time. At the same time,
store the fault code in the memory of ECU, and start failure protection function to maintain the engine
operation. In addition, the maintainer can trigger self-diagnosis function of ECU through specific steps,
and read the fault code and data stream stored by ECU through the fault diagnosis connector, which can
provide the basis for fault diagnosis.
Besides, ECU also has the function of controlling the power supply of the electronic control system
and providing stable reference voltage for some sensors.
Installment position
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Electrical schematic map
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3.4 Engine Control System Common Fault Diagnosis
3.4.1 Electronic control system common failure and main causes
1. ECM failure
Under normal circumstances, ECM has a good reliability, and will not fail in normal use. Most
failures of ECM are by not properly used or caused by improper maintenance. Main reasons of ECM
failure are the following:
1 The ECM power circuit is faulty, causing ECM not to work.
2 Unplug the ECM harness connector while the power is on, causing ECM damage due to
momentary high voltage.
3 The operation due to water or damp, resulting in ECM internal circuit short circuit or electronic
components damaged; or the plug in the terminal is poor contact because of the oxidation.
4 The ECM interior is damaged. When the ECM is completely out of service due to damage and
power failure, the engine failure warning light on the instrument platform won't light up when the
ignition switch is turned on. The engine cannot start because it is not ignited and sprayed with oil.
5 If there is some damage to the control program of ECM or some of its input and output circuits
are damaged, some of the functions of the electronic control system will be abnormal. For example,
individual cylinders will not inject fuel and idling automatic control will fail.
2. Sensor failure
Sensor failures are in the following forms.
1 Internal sensor failures, such as the internal circuit open circuit, short circuit or internal
components aging, damage and other failures.
2 External sensor control circuit failure, such as the sensor power circuit, ground circuit, the
signal circuit of the short circuit, open circuit and so on.
3 Sporadic failures internal or external the sensor, such as poor contact of internal components or
plugs, and occasional malfunctions at work.
When the sensor internal or external circuit is open or short circuit fault, the sensor signal value
will exceed the normal range, this failure is easily measured by ECM self-diagnostic system. The ECM
immediately lights the engine fault warning light on the dash and notes the fault code in memory and
starts fail-safe control to maintain the engine running.
When the sensor internal components have aging damage, the signal value, although not beyond the
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normal range, does not meet with the actual parameters detected. This failure is sometimes not detected
by ECM self-diagnostic system and fails to initiate fail-safe control, which can result in abnormal engine
operation.
3.Actuator failure
Actuators containing both electronic components and mechanical parts inside, is the most prone to
failure components in electronic control system . When an actuator fails, the ECM control commands
will not be executed properly, causing the engine to malfunction. Common causes of failure are the
following:
1 The electronic components in the actuator are damaged or the internal circuit is short-circuit、
open-circuit or other hardware failure.
2 The mechanical parts in the actuator can not work normally due to wear and jamming.
3 Aging and other reasons in the electronic components or mechanical parts in actuator lead to
slow response.
4 Actuator internal electronic components exist virtual connection or mechanical parts exist with
the abnormal gap; the actuator occasionally malfunctions due to temperature or other external factors.
4. Control circuit failure
The abnormal control circuit between ECM and sensor, actuator, power supply and iron can also
make the sensors, actuators and ECM of the electronic control system not work properly, and cause
various faults of the engine. The main reasons of the common control circuit fault are as follows:
1 Power fuse due to bad contact, overload fuse and other reasons causes the system power circuit
failure.
2 The grounding wire of a sensor, actuator, or ECM is poorly pitched, resulting in failures of
sensor, actuator, or ECM abnormal operation.
3 The connector in the control circuit has been disassembled for many times, causing the plug or
terminal to loosen、oxidate ,results in improper contact of the plug;
4 Connecting wire aging, internal fracture or skin rupture, resulting in open circuit or short circuit
fault.
3.4.2 Electronic control system common fault diagnose
1.Engine can not be started
When ignition switch is ON, the starter can drive engine to turn normally, but can not start, and
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there is no sign of starting vehicle. Then it must be at least one of ignition control system, fuel control
systems or ECM in engine electronic control system is completely disabled. If starter can drive engine to
normal rotation, and there is a slight sign of starting vehicle, but can not start. It indicates that although
function of ignition system, fuel control system and ECM is abnormal, but it is not completely
functional. The reasons for this failure are that the high pressure spark is too weak or the ignition time is
not correct, the mixture is too thin, the mixture is too thick, and the cylinder pressure is too low. The
reasons for the failure of engine can’t start are usually the followings:
1 The fuel pump does not work.
2 Fuel injector does not work.
3 Ignition system does not ignite.
4 Fuel pressure is too low.
5 Ignition advance angle is incorrect.
6 High pressure spark is too weak.
7 Injector leaks oil.
8 ECM does not work.
Check Steps:
1 To failure of engine can not start, generally should first check fuel storage situation of fuel tank.
if there is no fuel in the tank, it should be refueling.
2 Read fault code, according to the fault code to find the corresponding fault cause. The main
components that may affect engine starting are crankshaft position sensor, coolant temperature sensor,
inlet temperature pressure sensor and so on.
3 Check ignition system. If engine does not ignite, engine can not also start. Therefore, ignition
system should be checked whether there is failure before further inspection.Refer to engine electrical
equipment for specific operation
4 Check whether or not the injector is working properly.
5 Check whether fuel pump is working properly. Make electric fuel pump run artificially
(temporarily supply it with a specified voltage). You should be able to hear the sound of fuel pump
running or to feel the pressure pulsation of fuel when you hold the inlet pipe with your hand.
6 Check fuel pressure. he standard value should be around 350KPa
2. Engine hard to start
Engine starting difficulty refers to engine can drive engine to rotate in normal speed, there is
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obvious sign of vehicle starting, but can not start; or need to start several times; or need starter to drive
for a long time before engine can start; or start after flameout, unable to normal running. Main reason for
hard starting are in the followings:
1 The fuel pressure is too low, making the mixture too thin when starting.
2 Coolant temperature sensor failure, resulting in the mixture is too thin or too thick.
3 The injector leaks oil,resulting in bad spray atomization
4 Fuel injector is blocked, making the fuel injection amount is less or no, leading to the difficulty
of starting.
5 Ignition timing is abnormal or poor performance of spark plug or ignition coil in ignition
system.
6 There is failure in ECM starting control circuit.
7 The pressure of the cylinder is too low. The combustible mixture in the cylinder has poor
combustion conditions and is not easy to fire.
Check Steps:
1 Read fault code, check fault code related components.
2 Check whether there is leaking in intake system. Check carefully to see if the relevant intake
pipe is broken, the coupling clamps are loose, and the crankcase ventilation system hose is well
connected.
3 Check whether idling related component is working properly.
4 Check fuel pressure, if the pressure is too low, check if fuel pump is working properly or the
gasoline filter is blocked.
5 Check if the mixture is too thick during starting (black smoke, sharp unburned gasoline, etc.).
If the mixture is too thick, check the fuel pressure, coolant temperature sensor, intake pressure sensor,
etc.
6 If the mixture is normal, focus on the ignition system. Remove spark plug, check whether there
is aging, serious carbon deposition or spark plug gap is too large in spark plug, these conditions may
affect the starting performance. Check ignition control circuit to see if there are open circuit, short
circuit and so on. Do fire test, if necessary.
7 Check the cylinder pressure. If the cylinder pressure is lower than 1.1Mpa, the engine should
be disassembled and inspected for mechanical failure.
If all above are normal, try to replace ECM.
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3. Engine idling unstable
If engine starts normally, its idle speed is unstable, the engine has obvious jitter and miss fire easily,
regardless of whether it is cold or warm. This phenomenon may be caused by the following reasons:
1 Fuel pressure is low.
2 Poor atomization、oil leakage or blockage of the injector;
3 Spark plug working not well.
4 Air inlet temperature pressure sensor failure.
5 Charcoal canister solenoid valve works at idle speed.
6 Cylinder pressure is too low or cylinder pressure difference is too large.
Check Steps:
1 Read fault code and repair according to the fault code.
2 Check whether there is air leakage or pipe connections are connected properly in air intake
system.
3 Check whether there is stuck, carbon deposit, oil or excessive dust when throttle valve
working.
4 Do cylinder breaking test, cut off one cylinder one by one in idle speed , and check whether
engine speed drop is equal. If engine speed of some cylinder is basically unchanged when the cylinder is
broken, it indicates that the cylinder is not working well or not work. Check whether there is fault in
cylinder ignition coil, spark plug or fuel injector, and whether there are faults in the related control
circuit. Check cylinder pressure, if the cylinder pressure is abnormal, further check the valve clearance,
cylinder wear and valve sealing.
5 Check fuel pressure, if abnormal please check the oil pump and related fuel lines.
6 Check air inlet temperature pressure sensor signal. If not normal, proceed to the next step.
4. Idling engine speed too high
Electric control system can let engine run in a faster speed when vehicle is cold, and let engine
returned to normal idle speed when vehicle is warm. If engine still keeps high idle speed after warming
vehicle, that is, the idle speed is too high, it usually has the following reasons.
1 Throttle failure or air leakage in intake pipe.
2 Accelerator pedal failure.
3 Coolant temperature sensor fault
4 Carbon canister solenoid valve failure
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Check Steps:
1 Read fault code and repair according to the fault code.
2 Check whether there is stuck, carbon deposit in electronic throttle valve.
3 Check water temperature sensor.
4 When A/C switch is ON, if engine speed does not change, check whether the relevant vehicle
control signal is normal.
5 Tighten hose connected to intake manifold, if engine speed decreases, it indicates that there is
air leakage in the crankcase ventilation system or the carbon canister solenoid valve, so the pipeline and
solenoid valve of carbon canister should be further checked.
5. Idling engine speed fluctuating too much
If engine speed fluctuates continuously during idling, it may be engine fuel system, ignition system
or electronic throttle valve related failure. It can be considered from the following points.
1 Poor atomization or blockage of the injector;
2 Spark plug bad ignition.
3 Wrong water temperature sensor signal.
4 Oxygen sensor failure.
5 Electronic throttle valve or other control circuit failure.
Check Steps:
1 Read fault code Pay special attention to coolant temperature sensor, inlet temperature pressure
sensor, oxygen sensor.
2 Whether there is electronic throttle - related fault code or not, if there is, check the
corresponding sensors, actuators and their control circuits.
3 Disconnect each cylinder ignition coil or fuel injector wiring harness connector one by one
during idling, check whether the engine cylinders work steadily. If engine speed drop is not obvious
when disconnecting some cylinder ignition coil or fuel injector wiring harness connector, it indicates
the cylinder work normally, should check spark plug, high voltage wire and fuel injector.
4 Measure resistance of coolant temperature sensor at different temperatures, and check whether
accord with the standard value. If it is abnormal, the water temperature sensor should be replaced.
5 Check inlet temperature pressure sensor.
6. Easy to miss fire when idling
Main reasons for easy to miss fire when idling are the followings.
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1 Ignition system is not working properly, it is easy to miss fire during engine running.
2 Fuel system works abnormally, such as low fuel pressure, abnormal fuel pump working, fuel
injector blockage, and so on.
3 Idle speed instability or idling engine speed too low;
4 Electronic throttle valve fault;
5 Bad contact in wiring harness connector of control system circuit.
Check Steps:
1 Read fault code and check related parts according to the fault code.
2 Check whether there is lack power during driving, if there are acceleration weakness、
acceleration slow reaction; check fuel pressure, if it is abnormal, check fuel system related components.
3 If idle speed is unstable, or even flameout during idling when A/C is on, check whether or not
there is failure in A/C switch, there is failure in ECU connecting circuit.
4 If all the above checks are normal, check whether there is bad contact in engine control wire
harness.
7. Power not enough
Lack power means that vehicle accelerates slow, accelerator pedal is still insufficient, rotating
speed is not high or climbing slope is weak, etc. Main reasons for the failure include the following
points.
1 Air filter blocked or inlet system pipe connection loosen.
2 Electronic throttle valve fault;
3 Fuel pressure is too low.
4 Poor atomization or blockage of the injector;
5 Water temperature sensor fault
6 Temperature pressure sensor failure
7 wrong ignition timing or high pressure spark is too weak.
8 Abnormal cylinder pressure.
Check Steps:
1 Check whether there is blockage in air filter, whether air intake system connection is normal. If
abnormal, should be handled.
2 Read the fault code and check the components associated with the fault code. Sensors and
actuators that affect dynamic include water temperature sensor, air inlet temperature pressure sensor,
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spark plug, fuel injector, ignition coil, etc.
3 Check spark plug and ignition coil.
4 Check ignition timing.
5 Check fuel pressure, If pressure is too low, further check fuel pump, fuel line and so on.
6 Check the injector, See if there are serious problems such as carbon deposition.
7 Measure cylinder pressure.
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3.5 Engine Control System Fault Diagnosis Process
3.5.1 Diagnose according to the fault code
1.Instruction
1) The following overhaul would be carried out only it has been confirmed as the current
steady-state failure , otherwise will cause the diagnosis to be wrong.
2) The following "multimeter" occasion refers to the digital multimeter; prohibit the use of pointer
multimeter on the electronic control system line inspection.
3) check vehicles with anti-theft system, if ECM replacement occurs in "next steps", pay attention
to matching after ECM replacement.
4) If the fault code shows that the voltage of a circuit is too low, it means the circuit may be shorted
or open to ground. If the fault code shows that a circuit voltage is too high, it means that the circuit may
have a short circuit to the power supply. If the fault code shows a circuit fault, it means there may be a
circuit break in the circuit or there are multiple line faults.
2. Fault diagnosing assist
1) If the fault code can not be cleared, the fault is a steady-state fault; if it is an occasional fault,
check the harness connector for looseness.
2) In the overhaul process, do not neglect the impact of car maintenance 、 cylinder pressure 、
mechanical ignition timing and so on to the system.
3. Fault Code Diagnosis
■ Related ECM pins mentioned below refer to actual wiring harness diagram.
Engine Maintenance Manual Engine electric control system
132
Fault code
P0012
Intake VCP camshaft phase is large
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Wire connection terminal:
MT62.1
VCP
control
Normal
measuring signal
Variable timing control
signal:
43
B
0～1000mV
Main relay:
\
A
12V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine
running failure duration
time
﹥
2 seconds
1. Connectors are not plugged in
2. Variable timing control signal circuit
has open circuit
3. Variable timing control signal circuit
has short circuit to ground
4.Main relay circuit fault
5. Sensor damaged
6.Failure of timing control signal input
interface on ECM
1. plug the connector
again
2.repair wire harness
3.Repair wire harness
4.Repair wire harness
5.Replace the sensor
6.Replace ECM
Fault code
P0026
Intake VCP hydraulic pressure control valve vised
Set up emergency control plan:
Turn on the fault lights until the fault is gone,close air inlet
VCP hydraulic pressure control valve.
Wire connection
terminal:
MT62.1
VCP control
Normal measuring
signal
Main relay:
\
A
12V
Variable timing control
signal:
43
B
0-12V square wave
Judging
condition
Possible fault reasons
Referred failure
troubleshooting
duration time﹥2
seconds
1. Hydraulic control valve drive circuit has
short circuit to the system power anode
2. Hydraulic control valve is damaged
3. ECM fault
1. Repair wire harness
2. Replace control valve
3. Replace ECM
Fault code
P0107
Intake pressure sensor circuit low voltage or open circuit
Set up emergency control plan:
Turn on the fault lights until the fault is gone
When the engine stops：100kPa
When the engine is idle：≈32kPa
when engine is running:The manifold pressure changes
with the throttle opening
Wire connection terminal:
MT62.1
Pressure
sensor
Normal
measuring signal
5V reference voltage:
39
2
5V
manifold pressure signal:
43
1
0.5
～
4.5V
Engine Maintenance Manual Engine electric control system
133
Sensor signal ground
45
4
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
engine running
No TPS fault
MAP﹤14.017KPa
RPM﹤1050 rpm
TPS﹥18.75 %
fault duration time﹥
2.5 seconds.
1. The connector is not solid
2. Pressure signal circuit open circuit
3. Pressure signal circuit has short circuit
to earth
4. 5V reference voltage circuit open
5. Sensor signal ground circuit open
6. 5V reference voltage is opposite the
reference ground（This failure may cause
sensor damage）
7. Sensor damage
8. MAP signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
5. Repair wire harness
6. Repair wire harness
7. Replace sensor
8. Replace ECM
Fault code
P0108
Intake pressure sensor circuit high voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
When the engine stops
：
100kPa
When the engine is idle
：
≈32kPa
when engine is running: The manifold pressure changes
with the throttle opening
Wire connection terminal:
MT62.1
Pressure
sensor
Normal
measuring signal
5V reference voltage:
39
2
5V
manifold pressure signal:
43
1
0.5～4.5V
Sensor signal ground
45
4
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running
no TPS fault
MAP
﹥
98.117kPa
TPS
﹤
19.141%
fault duration
﹥
2.5seconds
1. The constrained pressure signal
circuit is short-circuited to the 5V
reference voltage or power
positive pole
2. Sensor is damaged
3. Pressure signal input interface
fault on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM
Engine Maintenance Manual Engine electric control system
134
Fault code
P0112
Intake temperature sensor circuit low voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
The air inlet temperature is equal to the coolant
temperature，but is no more than 44.25 C.
Wire connection terminal:
MT62.1
temperatur
e
sensor
Normal
measuring signal
Air inlet temperature signal:
15
3
0.5
～
4.5V
Sensor signal ground
45
4
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running time﹥120
seconds MAT
﹥-38.25C
fault duration time﹥2.5
seconds
1. The connector is not solid
2. The temperature signal circuit
open
3. Sensor signal ground open
4. The temperature signal circuit is
short-circuited to the positive pole of
the power supply
5. Sensor damage
6. signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
5. Replace sensor
6. Replace ECM
Fault code
P0113
Intake temperature sensor circuit high voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
The air inlet temperature is equal to the coolant
temperature
，
but is no more than 44.25 C.
Wire connection terminal:
MT62.1
Air inlet
temperatur
e sensor
Normal
measuring signal
Air inlet temperature signal:
15
3
0.5～4.5V
Sensor signal ground
45
4
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running time
﹥
60
seconds MAT
﹥
148.5C
fault duration time
﹥
2
seconds
1. Temperature signal circuit is
short-circuited to earth
2. Sensor is damaged
3. Pressure signal input interface
fault on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM
Fault code
P0117
Coolant temperature sensor circuit low voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Start with air inlet temperature
，
Fixed after increasing to
79.5 degrees over time
Wire connection terminal:
MT62.1
Coolant temperature
sensor
Normal
measuring signal
Engine Maintenance Manual Engine electric control system
135
Coolant temperature signal:
20
A
0.5
～
4.5V
Sensor signal ground
46
C
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running time﹥10
seconds CTS
﹤-38.25C
fault duration time﹥2
seconds
1. The connector is not solid
2. The temperature signal circuit
open
3. Sensor signal ground open
4. The temperature signal circuit is
short-circuited to the positive pole of
the power supply
5. Sensor damage
6. signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
5. Replace sensor
6. Replace ECM
Fault code
P0118
Coolant temperature sensor circuit high voltage or open
circuit
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Start with air inlet temperature，Fixed after increasing to
79.5 degrees over time
Wire connection terminal:
MT62.1
Coolant temperature
sensor
Normal
measuring signal
Coolant temperature signal:
20
A
0.5
～
4.5V
Sensor signal ground
46
C
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running time﹥2
seconds CTS
﹥135C
fault duration time﹥2
seconds
1. Temperature signal circuit is
short-circuited to earth
2. Sensor is damaged
3. Pressure signal input interface
fault on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM
Fault code
P0122
ETC throttle valve position sensor
１＃
circuit low
voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Idle
，
set throttle valve position sensor opening 0%
；
other opening changes with rotating speed throttle
valve position sensor auto-zero function stops
clear function stops
Wire connection terminal:
MT62.1
Throttle valve position
sensor
Normal
measuring signal
5V reference voltage:
39
A
5V
Throttle valve position 1
signal:
14
D
0.5～4.5V
Sensor signal ground
45
F
0V
Engine Maintenance Manual Engine electric control system
136
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running，rotate
speed﹤3000rpm
no MAP fault，and MAP
﹤70kpa
fault duration time﹥2 秒
1. sensor signal circuit is
short-circuited to to power positive
pole or reference voltage circuit
2. Sensor is damaged 3.
Pressure signal input interface fault
on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM
Fault code
P0123
ETC throttle valve position sensor 1
＃
circuit high
voltage or open circuit
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Idle
，
set throttle valve position sensor opening 0%
；
other opening changes with rotating speed throttle
valve position sensor auto-zero function stops
clear function stops
Wire connection terminal:
MT62.1
Throttle valve
position sensor
Normal
measuring signal
5V reference voltage:
39
A
5V
Throttle valve position 1
signal:
14
D
0.5～4.5V
Sensor signal ground
45
F
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time
﹥
2
seconds
1. The connector is not solid
2. sensor signal circuit open
3. Sensor signal has short circuit to
ground
4. Sensor damage
5. signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Replace sensor
5. Replace ECM
Fault code
P0131
Front oxygen sensor short circuit to low voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone and turn off
the ignition switch
System closed - loop working time delayed
Wire connection terminal:
MT62.1
Heating
oxygen
sensor
Normal
measuring signal
System main power:
\
D
12V
Heating Drive:
41
C
0V
oxygen sensor high signal:
22
B
0
～
1000mV
fluctuation
Engine Maintenance Manual Engine electric control system
137
oxygen sensor low signal:
46
A
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time﹥1 seconds
1. The heating drive circuit is
short-circuited to the positive pole of
the power supply
2. Sensor is damaged
3. Pressure signal input interface
fault on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM
Fault code
P0132
Front oxygen sensor short circuit to high voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone and turn off
the ignition switch
System closed - loop working time delayed
Wire connection terminal:
MT62.
1
Heating
oxygen
sensor
Normal
measuring signal
System main power:
\
D
12V
Heating Drive:
41
C
0V
oxygen sensor high signal:
22
B
0～1000mV
fluctuation
oxygen sensor low signal:
46
A
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
No main relay failure
duration time﹥1 seconds
1. The connector is not solid
2. The heating drives the circuit open
3. Heat drive line to ground short
circuit
4. Sensor damage
5. signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Replace sensor
5. Replace ECM
Fault code
P0133
front oxygen sensor responds too slowly
Set up emergency control plan:
Turn on the fault lights until the fault is gone and turn off
the ignition switch
System closed - loop working time delayed
Wire connection terminal:
MT62.1
Heating
oxygen
sensor
Normal
measuring signal
System main power:
\
D
12V
Heating Drive:
41
C
0V
Engine Maintenance Manual Engine electric control system
138
oxygen sensor high signal:
22
B
0
～
1000mV
fluctuation
oxygen sensor low signal:
46
A
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
No main relay failure
duration time﹥1 seconds
1. The connector is not solid
2. The heating drives the circuit open
3. Heat drive line to ground short
circuit
4. Sensor damage
5. signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Replace sensor
5. Replace ECM
Fault code
P0137
Rear oxygen sensor short circuit to low voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone and turn off
the ignition switch
System closed - loop working time delayed
Wire connection terminal:
MT62.1
Heating
oxygen
sensor
Normal
measuring signal
System main power:
\
D
12V
Heating Drive:
41
C
0V
oxygen sensor high signal:
22
B
0～1000mV
fluctuation
oxygen sensor low signal:
46
A
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time
﹥
1 seconds
1. The heating drive circuit is
short-circuited to the positive pole of
the power supply
2. Sensor is damaged
3. Pressure signal input interface
fault on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM
Fault code
P0138
Rear oxygen sensor short circuit to high voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone and turn off
the ignition switch
System closed - loop working time delayed
Wire connection terminal:
MT62.1
Heating
oxygen
sensor
Normal
measuring signal
Engine Maintenance Manual Engine electric control system
139
System main power:
\
D
12V
Heating Drive:
41
C
0V
oxygen sensor high signal:
22
B
0～1000mV
fluctuation
oxygen sensor low signal:
46
A
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
No main relay failure
duration time
﹥
1 seconds
1. The connector is not solid
2. The heating drives the circuit open
3. Heat drive line to ground short
circuit
4. Sensor damage
5. signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Replace sensor
5. Replace ECM
Fault code
P0222
ETC throttle valve position sensor 2＃circuit low voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Idle
，
set throttle valve position sensor opening 0%
；
other opening changes with rotating speed throttle
valve position sensor auto-zero function stops
clear function stops
Wire connection terminal:
MT62.1
Throttle valve
position sensor
Normal
measuring signal
5V reference voltage:
39
A
5V
Throttle valve position 2
signal:
16
E
0.5～4.5V
Sensor signal ground
45
F
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running
，
rotate
speed
﹤
3000rpm
no MAP fault
，
and MAP
﹤
70kpa
fault duration time
﹥
2s
1. sensor signal circuit is
short-circuited to power positive pole
or reference voltage circuit
2. Sensor is damaged
3. Pressure signal input interface
fault on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM
Fault code
P0223
ETC throttle valve position sensor 2＃ circuit high
voltage or open circuit
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Idle ，set throttle valve position sensor opening 0%；
other opening changes with rotating speed throttle
valve position sensor auto-zero function stops
clear function stops
Wire connection terminal:
MT62.1
Throttle valve position
sensor
Normal
measuring signal
Engine Maintenance Manual Engine electric control system
140
5V reference voltage:
39
A
5V
Throttle valve position 2
signal:
16
E
0.5～4.5V
Sensor signal ground
45
F
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time
﹥
2 seconds
1. The connector is not solid
2. sensor signal circuit open
3. Sensor signal has short circuit to
ground
4. Sensor damage
5. signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Replace sensor
5. Replace ECM
Fault code
P0325
Knock sensor failure
Set up emergency control plan:
Turn on the fault lights until the ignition switch is off
Adopt safe ignition advance angle table
Wire connection terminal:
MT62.1
knock sensor
Normal
measuring signal
Knock signal high:
25
0-1V
Knock signal low:
37
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine rotate speed﹥
2000rpm
MAP﹥50kPa
fault duration time﹥5
seconds
1. The connector is not solid
2. The knock signal circuit open
3. Sensor signal ground short circuit
4. Knock signal other circuit short
circuit
5. Sensor damage
6. Signal output interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
5. Replace sensor
6. Replace ECM
Fault code
P0336
Crankshaft position sensor circuit signal interfere
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Wire connection terminal:
MT62.1
Crankshaft position
sensor
Normal
measuring signal
Sensor signal :
33
A
〉
400mV sine
wave
（
with
sensor B
）
voltage signal:
38
C
〉400mV sine
wave（with
sensor A）
System ground wire:
46
B
0V
Judging condition
Possible fault reasons
Referred failure
Engine Maintenance Manual Engine electric control system
141
troubleshooting
Engine running
The number of teeth
entering ECM for 5
consecutive cycles is not
equal to 58
1. The signal line is badly shielded
2. There are metal objects in the 58x
gear ring
1. Use shield wire
2. Clean 58x gear ring
Fault code
P0337
Crankshaft position sensor circuit no signal
Set up emergency control plan:
Turn on the fault lights until the fault is gone
the engine failed to start
Wire connection terminal:
MT62.1
Crankshaft position
sensor
Normal
measuring signal
Sensor signal :
33
A
〉400mV sine
wave（with
sensor B）
voltage signal:
38
C
〉
400mV sine
wave
（
with
sensor A
）
System ground wire:
46
B
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Start engine No
engine speed signal MAP
reduces 2.9509kPa
System voltage drops 0.8V
speed<4km/h
duration time﹥2 seconds
1. The connector is not solid
2. The signal is reversed high and
low
3. Signal circuit open
4. Signal circuit other short circuit
5. Sensor damage
6. Signal input interface fault on
ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
5. Replace sensor
6. Replace ECM
Fault code
P0341
Camshaft position sensor reasonable fault
Set up emergency control plan:
Turn on the fault lights until the fault is gone
he injection sequence has a 50% chance of 360 degrees of
dislocation
Wire connection terminal:
MT62.1
Camshaft
position
sensor
Normal
measuring signal
5V reference voltage:
39
C
5V
Camshaft signal:
21
A
0-5V square
wave
Sensor signal ground:
45
B
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine Maintenance Manual Engine electric control system
142
Engine running
1. The connector is not solid
2. reference voltage circuit
open
3. signal ground open
4. Camshaft signal open
5. Sensor damage
6. interface fault on ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
5. Replace sensor
6. Replace ECM
Fault code
P0340
Camshaft position sensor no signal
Set up emergency control plan:
Turn on the fault lights until the fault is gone
he injection sequence has a 50% chance of 360 degrees
of dislocation
Wire connection terminal:
MT62.1
Camshaft position
sensor
Normal
measuring signal
5V reference voltage:
39
C
5V
Camshaft signal:
21
A
0-5V square
wave
Sensor signal ground:
45
B
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running
1. The connector is not solid
2. reference voltage circuit open
3. signal ground open
4. Camshaft signal open
5. Sensor damage
6. interface fault on ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
5. Replace sensor
6. Replace ECM
Fault code
P0351
1# ignition coil malfunction
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Stop spraying oil on 1 cylinder
The target idling is raised to 1200rpm
Wire connection terminal:
MT62.1
ignition coil
Normal
measuring signal
System main power:
\
12V
1 cylinder drive:
04
0-12V
approximate
square wave
signal induction
peak〉300V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time﹥1.25
seconds
1. 1 cylinder drive circuit and power
positive short circuit
2. Ignition coil is damaged
3. ECM fault
1. Repair wire harness
2. Replace ignition coil
3. Replace ECM
Engine Maintenance Manual Engine electric control system
143
Fault code
P0352
2# ignition coil malfunction
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Stop spraying oil on 1 cylinder
The target idling is raised to 1200rpm
Wire connection terminal:
MT62.1
ignition coil
Normal
measuring signal
System main power:
\
12V
2 cylinder drive:
81
0-12V
approximate
square wave
signal induction
peak
〉
300V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time﹥1.25
seconds
1. 2 cylinder drive circuit and power
positive short circuit
2. Ignition coil is damaged
3. ECM fault
1. Repair wire harness
2. Replace ignition coil
3. Replace ECM
Fault code
P0353
3# ignition coil malfunction
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Stop spraying oil on 1 cylinder
The target idling is raised to 1200rpm
Wire connection terminal:
MT62.1
ignition coil
Normal
measuring signal
System main power:
\
12V
3 cylinder drive:
01
0-12V
approximate
square wave
signal induction
peak〉300V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time
﹥
1.25
seconds
1. 3 cylinder drive circuit and power
positive short circuit
2. Ignition coil is damaged
3. ECM fault
1. Repair wire harness
2. Replace ignition coil
3. Replace ECM
Fault code
P0354
4# ignition coil malfunction
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Stop spraying oil on 1 cylinder
The target idling is raised to 1200rpm
Wire connection terminal:
MT62.1
ignition coil
Normal
measuring signal
Engine Maintenance Manual Engine electric control system
144
System main power:
\
12V
4 cylinder drive:
62
0-12V
approximate
square wave
signal induction
peak〉300V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time﹥1.25
seconds
1. 4 cylinder drive circuit and power
positive short circuit
2. Ignition coil is damaged
3. ECM fault
1. Repair wire harness
2. Replace ignition coil
3. Replace ECM
Fault code
P0458
Carbon canister electromagnetic valve short circuit to
low voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
close charcoal canister solenoid valve
Wire connection terminal:
MT62.1
Carbon canister
solenoid valve
Normal
measuring signal
System main power:
\
B
12V
Solenoid valve drive:
64
A
0-12V square
wave
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time﹥2 seconds
1. Solenoid valve drive circuit has short
circuit to the system power anode
2. Solenoid valve is damaged
3. ECM fault
1 .repair wire
harness
2. Replace control
valve 3.
Replace ECM
Fault code
P0459
Carbon canister electromagnetic valve short circuit to
high voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
close charcoal canister solenoid valve
Wire connection terminal:
MT62.1
Carbon canister
solenoid valve
Normal
measuring signal
System main power:
\
B
12V
Solenoid valve drive:
64
A
0-12V square
wave
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time
﹥
5 seconds
1. The connector is not solid
2. Solenoid valve drive circuit has
short circuit to the system power
negative pole
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
Engine Maintenance Manual Engine electric control system
145
3. Solenoid valve drive circuit open
4. the circuit connected with
system main power circuit open
5. Solenoid valve damage
6. Fault on ECM
5. Replace solenoid
valve 6. Replace
ECM
Fault code
P0480
Low speed fan failure
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Fan does not working
（
open circuit
），
The high speed fan
starts and works constantly when the water temperature
rises to 98 degrees
（
short circuit to ground
）
Wire connection terminal:
MT62.1
Low speed fan relay
Normal
measuring signal
Battery:
\
Instructions provided
by car factory
12V
Relay drive:
65
Instructions provided
by car factory
0V（working），
12V（stopping）
Judging condition
Possible fault reasons
Referred failure
troubleshooting
duration time
﹥
3 seconds
1. The connector is not solid
2. Relay drive circuit has short circuit
to the system power negative pole
3. Relay drive circuit open
4. the circuit connected with
battery open
5. Relay damage
6. fault on ECM
1. Plug again
2. Repair wire harness
3. Repair wire harness
4. Repair wire harness
5. Replace relay
6. Replace ECM
Fault code
P0562
System voltage is low
Set up emergency control plan:
Turn on the fault lights until the fault is gone
The system stopped spraying oil
Wire connection terminal:
MT62.1
Ignition switch
Normal
measuring signal
Ignition switch
68
Refer to electrical
system instructions
12V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Turn on ignition switch
system voltage﹤7.6V
duration time〉5seconds
1. The generator regulator is
damaged
2. Wrong usage of low voltage
battery
1.Replace the damaged
generator regulator 2.
Use correct battery
Fault code
P0563
System voltage is high
Set up emergency control plan:
Turn on the fault lights until the fault is gone
The system stopped spraying oil
Engine Maintenance Manual Engine electric control system
146
Wire connection terminal:
MT62.1
Ignition switch
Normal
measuring signal
Ignition switch
68
Refer to electrical
system instructions
12V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Turn on ignition switch
system voltage〉17.2V
duration time〉5seconds
1. The generator regulator is
damaged
2. Wrong usage of high voltage
battery
1.Replace the damaged
generator regulator 2.
Use correct battery
Fault code
P2122
Electronic accelerator pedal position sensor 1# circuit
low voltage or open circuit
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Wire connection terminal:
MT62.1
Accelerato
r position
sensor 1
Normal
measuring signal
5V reference voltage:
70
2
5V
Accelerator pedal signal 1:
41
4
0.5
～
4.5V
Sensor signal ground:
74
3
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running
failure duration time﹥2.5
seconds
1. Accelerator position
sensor signal circuit is
short-circuited to the 5V
reference voltage or power
positive pole
2. Sensor is damaged
3. Pressure signal input
interface fault on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM
Fault code
P2123
Electronic accelerator pedal position sensor 1# circuit
high voltage
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Wire connection terminal:
MT62.1
Accelerato
r position
sensor 1
Normal
measuring signal
5V reference voltage:
70
2
5V
Accelerator pedal signal 1:
41
4
0.5
～
4.5V
Sensor signal ground:
74
3
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine Maintenance Manual Engine electric control system
147
Engine running
failure duration time
﹥
2.5
seconds
1. The connector is not solid
2. sensor signal circuit open
3. Sensor signal has short
circuit to ground
4. Sensor damage
5. signal input interface fault
on ECM
1. Plug again
2. Repair wire
harness 3.
Repair wire harness
4. Replace sensor
5. Replace ECM
Fault code
P2127
Electronic accelerator pedal position sensor 2# circuit
low voltage or open circuit
Set up emergency control plan:
Turn on the fault lights until the fault is gone
Wire connection terminal:
MT62.1
Accelerato
r position
sensor 2
Normal
measuring signal
5V reference voltage:
66
1
5V
Accelerator pedal signal 2:
42
6
0.5～4.5V
Sensor signal ground:
76
5
0V
Judging condition
Possible fault reasons
Referred failure
troubleshooting
Engine running
failure duration time
﹥
2.5
seconds
1. Accelerator position
sensor signal circuit is
short-circuited to the 5V
reference voltage or power
positive pole
2. Sensor is damaged
3. Pressure signal input
interface fault on ECM
1. Repair wire harness
2. Replace sensor
3. Replace ECM