2.2.7.4 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 2.2.7.43 DTC P0562 P0563 

2. Intake 

Manifold 

Absolute 

Pressure (MAP) Sensor 

Refer to 2.2.7.18 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 2.2.7.26 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 2.2.7.35 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 2.2.7.53 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 2.2.8.1 Replacement of Engine 
Control Module. 

1.  ECM power supply circuit 

Refer to 2.2.7.43 DTC P0562 P0563 

2.  Mixture Too Thick 

Refer to 2.2.7.26 DTC P0171 P0172 
P1167 P1171 P2187 P2188 

High Fuel 
Consumption, 
Poor Fuel 
Economy 

Fault definition: 
oil consumption 

3.  Air Filter Blocked 

- 

115

4.  Poor Fuel Quality, Fuel 

Contamination 

5.  Abnormal Fuel Pressure 

6. Abnormal 

Injector 

Working 

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

7.  Electronic Throttle Body 

Refer to 2.2.7.53 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 

measured by 
actual road test is 
obviously high 
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 

High Fuel 
Consumption, 
Poor Fuel 
Economy 

Fault Definition: 
The actual road 

2.  Too much carbon residue in 

combustion chamber 

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

116

3.  Vacuum Hose Cracking or Kink, 

Connection Unreliable 

4. Exhaust 

Blocked: 

Three-Way 

Catalytic Converter Blocked, 
Muffler Internal Damage 

Refer to 2.7.5 Diagnostic Information 
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 

test fuel 
consumption is 
significantly 
higher than 
expected. In 
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 2.2.7.43 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 2.2.7.26 DTC P0171 P0172 
P1167 P1171 P2187 P2188 

7.  Electronic Throttle Body 

Refer to 2.2.7.53 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 2.2.7.35 DTC P0335 P0336 

117

1.  Too Much Oil in Combustion 

Chamber or Valve Seals 
Leakage 

2. Cylinder 

compression 

pressure 

is incorrect 

3.  Valve Stagnant or Leakage 

4.  Camshaft Convex Corner Wear 

5. Valve 

Timing 

Incorrect 

6. Valve 

Spring 

Broken 

7.  Too much carbon residue in 

combustion chamber 

8.  Abnormal Camshaft, Cylinder 

Hood, Piston, Connecting Rod 
and Bearing 

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

9. Exhaust 

Blocked: 

Three-Way 

Catalytic Converter Blocked, 
Muffler Internal Damage 

Refer to 2.7. Diagnostic Information 
and Procedures in the 2.7 Exhaust 
System 

1.  ECM power supply circuit 

Refer to 2.2.7.43 DTC P0562 P0563 

2.  Air Filter Blocked 

- 

3.  Abnormal Fuel Pressure 

4. Fuel 

Contamination 

5. Abnormal 

Injector 

Working 

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

6.  Electronic Throttle Body 

Refer to 2.2.7.53 DTC P2135 

7. Acceleration 

Pedal 

Position 

Sensor 

Refer to 2.2.7.54 DTC P2138 

8. Positive 

Crankcase 

Ventilation 

Valve 

9.  Evaporative Emission (EVAP) 

Canister Solenoid Valve 

10.  Knock Sensor (KS) system 

ignition delay is too large 

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

Fault definition 
for badness, 
instability, error 
or under speed of 
idle speed: 
starting in the 
course of idling. 

Engine runs 
unsteadily. In 
extreme cases, 
the engine or the 
vehicle will 
tremble. Engine 
idle speed under 
the condition that 
the throttle valve 
opening is certain 

The speed may 
be fluctuated. 
Any of these 
circumstances is 
likely to be 
serious enough to 
make the engine 
stall. 

11.  Spark Plug: Incorrect thermal 

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

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

118