3 

Inspect the wiring harness and connector. 

A.  Many intermittent faults are caused by vibration, distortion, uneven roads, and improper 

operation of components or connectors dislocation. 

B.  If the circuit resistance is too high, it may result in components can not work properly. Use a 

fault diagnosis tester to drive the actuators, if not working, inspect whether the resistance in 
the circuit is too high or other wire faults. 

 

4 

Reproduce the fault and use instruments to record engine control module data. 

A.  Connect a fault diagnosis tester and use the data record function to record road test data 

during the occurrence of the intermittent fault. After pressing the vehicle data recorder button, 
the scan tool can record engine control module data when intermittent fault occurs, and then 
the data can be used to identify the fault location. 

B.  Another diagnostic method is when the vehicle is driven connect a digital multimeter to the 

suspicious circuit. Digital multimeter abnormal readings may indicate the fault location. 

 

5 

Fault indicator gives intermittent light, but a DTC is not set in the system. 

The following conditions may cause intermittent fault indicator light, but the system does not set 
the DTC: 

A.  Electromagnetic interferences are caused by relay, solenoid valve or switch controlled by 

ECM, which work abnormally. 

B.  Non-original or after-sale accessories, such as phone, alarm, lamp or radio equipment, are not 

installed properly. 

C.  Intermittent fault indicator light control circuit short to ground. 

D.  Engine control module ground point is loose. 

 

6 Other 

inspections 

A.  Test whether Air-Conditioning compressor clutch diodes at both ends and other diodes are in 

open circuit. 

B.  Inspect whether there are following conditions existing in charging system: 

z  Generator rectifier fault within the electrical system may result in the alternating current 

signal interference. 

z  Generator output voltage is correct or not. If the generator output voltage is lower than 9V or 

higher than 18V, repair the charging system. 

 

7 

Enter Fault Symptom Table 

Next 

Next 

Next 

Next 

679

2.12.7.4 Fault Symptom Table 

If a fault occurs, but the DTC has not been stored in ECM, and its faulty reason can not be 
identified in the basic diagnostic, it is suggested to carry out the diagnostic and troubleshooting 
based on the listed order in the following table. 

Symptoms 

Suspected Faulty Items 

(Refer to the troubleshooting 
scheme) 

1.  ECM power supply circuit 

Refer to 2.12.7.43 DTC P0562 P0563

2. Intake  Manifold  Absolute 

Pressure (MAP) Sensor 

Refer to 2.12.7.18 DTC P0107 P0108

3.  Abnormal Fuel Pressure 

4.  Abnormal Injector Working 

Refer to 2.3.7 Diagnostic Information 
and Procedures in the 2.3 Fuel 
System 

5.  Mixture Too Thick 

6.  Mixture Too Thin 

Refer to 2.12.7.26 DTC P0171 P0172 
P1167 P1171 P2187 P2188 

7.  Ignition system: abnormal spark 

plug, abnormal ignition wires. 

8.  Knock Sensor (KS) system 

ignition delay is too large 

Refer to 2.10.7 Diagnostic 
Information and Procedures in the 
2.10 Ignition System 

9.  Crankshaft Position Sensor 

Refer to 2.12.7.35 DTC P0335 P0336

10.Abnormal thermostat 

2.8.7 Diagnostic Information and 
Procedures in the 2.8 Cooling System

Retardation, 
Engine Speed 
Decrease, Speed 
Instability 

Fault Definition: 
When pressing 
the accelerator 
pedal, there is no 
immediate 
response. This 
fault may occur 
at any vehicle 
speed. Start the 
vehicle for the 
first time (for 
example, start 
after parking), 
this fault is 
usually more 
obvious. In 
severe cases, this 
fault may lead to 
engine stalling. 

11. 

Abnormal Working of 
Generators 

Refer to 2.11.7 Diagnostic 
Information and Procedures in the 
2.11 Start and Charging System 

1.  Electronic Throttle Body 

Refer to 2.12.7.53 DTC P2135 

Fault Definition 
for engine 
stalling during 
air-conditioning 
works only: 
when Air- 
Conditioning is 
working, Engine 
Speed Instability 
or Stalling 

2. ECM 

See 2.12.8.1 Replacement of Engine 
Control Module. 

1.  ECM power supply circuit 

Refer to 2.12.7.43 DTC P0562 P0563

2.  Mixture Too Thick 

Refer to 2.12.7.26 DTC P0171 P0172 
P1167 P1171 P2187 P218 

3.  Air Filter Blocked 

- 

High Fuel 
Consumption, 
Poor Fuel 
Economy 

Fault definition: 
oil consumption 
measured by 
actual road test is 
obviously high 

4. Poor Fuel Quality, Fuel 

Contamination 

Refer to 2.3.7 Diagnostic Information 
and Procedures in the 2.3 Fuel 

680

5.  Abnormal Fuel Pressure 

6.  Abnormal Injector Working 

System 

7.  Electronic Throttle Body 

Refer to 2.12.7.53 DTC P2135 

8.  The driver has the following 

driving habits: 

• 

Air-Conditioning or defroster is 
always on 

• 

Tire pressure is incorrect 

• Vehicle 

Overload 

•  Accelerate Too Fast, Too 

Frequent 

- 

9.  Air Leakage In Intake System 

and Crankcase System 

10. Positive crankcase ventilation 

valve catching 

Refer to 2.4.6 Diagnostic Information 
and Procedures in the 2.4 Auxiliary 
Emission Control Devices 

11. Knock Sensor (KS) system 

ignition delay is too large 

12. Spark Plug: Incorrect thermal 

value, damp, crack, incorrect 
gap, excessive erosion, 
excessive carbon residue, 
contaminated by fuel 

13.  Spark Plug Wire Damage 

14. Ignition Coil Damage 

Refer to 2.10.7 Diagnostic 
Information and Procedures in the 
2.10 Ignition System 

15. 

Coolant Level Too Low, 
Thermostat Malfunction 

Refer to 2.8.7 Diagnostic Information 
and Procedures in the 2.8 Cooling 
System 

than 

Expected value 
In addition, the 
fuel consumption 
is also 
significantly 
higher than the 
previous road 
test. 

16.  Too Much Oil in Combustion 

Chamber or Valve Seals 
Leakage  17. Incorrect 
Cylinder Compression Pressure 
Ensure 

Refer to 2.6.7 Diagnostic Information 
and Procedures in the 2.6 Mechanical 
System 

1.  Valve Catching or Leakage, 

Broken Valve Spring, Incorrect 
Valve Timing 

2.  Too much carbon residue in 

combustion chamber 

3.  Vacuum Hose Cracking or 

Kink, Connection Unreliable 

Refer to 2.6.7 Diagnostic Information 
and Procedures in the 2.6 Mechanical 
System 

High Fuel 
Consumption, 
Poor Fuel 
Economy 

Fault Definition: 
The actual road 
test fuel 
consumption is 
significantly 
higher than 
expected. In 

4.  Exhaust  Blocked:  Three-Way  Refer to 2.7.5 Diagnostic Information 

681

Catalytic Converter Blocked, 
Muffler Internal Damage 

and Procedures in the 2.7 Exhaust 
System 

5.  Brake System Dragging or 

Operation Abnormally 

Refer to 6.2.4 Diagnostic Information 
and Procedures in 6 Brake System 

addition, the fuel 
consumption is 
also significantly 
higher than the 
previous road 
test. 

6. Electromagnetic  Interference 

(EMI) in the voltage circuit may 
lead to engine misfire.  Use  a 
fault diagnosis tester to monitor 
the engine speed to detect 
electromagnetic interference.
  Engine speed parameter 
suddenly increases while the 
actual engine speed does almost 
not change, then there is 
electromagnetic interference. If 
there is a malfunction, inspect 
whether there is a high voltage 
component in the vicinity of the 
ignition control circuit. 

- 

1.  ECM power supply circuit 

Refer to 2.12.7.43 DTC P0562 P0563

2.  Air Filter Blocked 

- 

3.  Abnormal Fuel Pressure 

4.  Abnormal Injector Working 

Refer to 2.3.7 Diagnostic Information 
and Procedures in the 2.3 Fuel 
System 

5.  Mixture Too Thick 

6.  Mixture Too Thin 

Refer to 2.12.7.26 DTC P0171 P0172 
P1167 P1171 P2187 P2188 

7.  Electronic Throttle Body 

Refer to 2.12.7.53 DTC P2135 

8.  Knock Sensor (KS) system 

ignition delay is too large 

9.  Spark Plug: Incorrect thermal 

value, damp, crack, incorrect 
gap, excessive erosion, 
excessive carbon residue, 
contaminated by fuel 

10.  Spark Plug Wire Damage 

11. Ignition Coil Damage 

Refer to 2.10.7 Diagnostic 
Information and Procedures in the 
2.10 Ignition System 

Lack of Fuel 
Supply, Misfire 

Fault Definition: 
After the engine 
speed increases, 
there is 
continuous 
pulsation, or 
jitter, usually 
even more 
noticeable with 
the engine load 
increases. When 
the engine speed 
is above 1,500 
rpm, the fault 
does not appear. 

12.  Crankshaft Position Sensor 

Refer to 2.12.7.35 DTC P0335 P0336

1.  Too Much Oil in Combustion 

Chamber or Valve Seals 
Leakage 

Lack of Fuel 
Supply, Misfire 

Fault Definition: 
After the engine 
speed increases, 
there is 

2. Cylinder 

compression 

pressure 

is incorrect 

Refer to 2.6.7 Diagnostic Information 
and Procedures in the 2.6 Mechanical 
System 

682