Chery A11. Manual - part 158

 

Maintenance Manual for Chery·Windcloud          

Marelli EFI System 

 

 

C.  Check spark plug to see if clearance is proper; 
D.  Check high voltage wire to see if resistance is 

too high; 

E.  Check intake conduit to see if it is worn out, 

etc. 

No 

Diagnosis 
Instruction 

 

Failure: too high circuit voltage of upstream oxygen sensor 

Step Operation 

Result  Solution 

1 

Connect scanner and commutator, and then turn 
ignition switch to “ON”. 

 

Go to next step

Yes 

Diagnosis 
Instruction 

2 

Start engine and idle it until coolant temperature is 
normal. Observe Oxygen Sensor Voltage to see if 
the indication quickly changes between 
100mV-900mV (at least 5 changes within 10 
seconds). 

No 

Go to next step

Yes 

Repair or 
replace wire 
harness 

3 

Check respectively the connections between Pin 20 
of ECU and Pin A of sensor connector, Pin 9 of 
ECU and Pin B of sensor connector (two thin wires 
on ECU wire harness, the two thick wires are 
heating coils) to see if they are short circuit to 
power. 

No 

Diagnosis 
Instruction 

 

Failure: signal error of upstream oxygen sensor

 

Step Operation 

Result  Solution 

1 

Connect scanner and commutator, and then turn 
ignition switch to “ON”. 

 

Go to next step

Yes 

Diagnosis 
Instruction 

2 

Start engine and idle it until coolant temperature is 
normal. Observe Oxygen Sensor Voltage to see if 
the indication quickly changes between 
100mV-900mV. 

No 

Go to next step

Yes 

Repair or 
replace wire 
harness 

3 

Check respectively the connections between Pin 20 
of ECU and Pin A of sensor connector, Pin 9 of 
ECU and Pin B of sensor connector (two thin wires 
on ECU wire harness, the two thick wires are 
heating coils) to see if open circuit occurs. 

No 

Diagnosis 
Instruction 

 

Failure: heating circuit error of upstream oxygen sensor 

Step Operation 

Result  Solution 

1 

Connect scanner and commutator, and then turn 
ignition switch to “ON”. 

 

Go to next step

 

20

 

Maintenance Manual for Chery·Windcloud          

Marelli EFI System 

 

Yes 

Go to next step

2 

Unplug oxygen sensor connector from wire harness, 
and check the voltage between Pin C 
(corresponding to white wire of oxygen sensor) and 
Pin D (corresponding to white wire of oxygen 
sensor, two thick wires on ECU wire harness) of the 
connector with a multimeter to see if it is around 
12V. 

No 

Go to Step 4 

Yes 

Go to next step

3 

Check the resistance between Pin C (white) and Pin 
D (white) of oxygen sensor with a multimeter to see 
if it is around 4.5Ω  (23 ± 5°C). 

No Replace 

sensor

Yes Replace 

fuse 

4 

Check the 10A fuse in oxygen sensor heating circuit 
to see if it is blown. 

No 

Go to next step

Yes 

Repair or 
replace wire 
harness 

5 

Check respectively the connections between Pin 28 
of ECU and Pin C (corresponding to white wire of 
oxygen sensor) of sensor connector, Pin 87 of main 
relay and Pin D (corresponding to white wire of 
oxygen sensor) of sensor connector to see if open or 
short circuit to power/ground occurs. 

No 

Diagnosis 
Instruction 

 

Failure: self-adaptation of air fuel ratio closed-loop control exceeds upper 

limit 

Step Operation 

Result  Solution 

1 

Connect scanner and commutator, and then turn 
ignition switch to “ON”. 

 

Go to next step

Yes 

Go to next step

2 

Start engine and idle it until coolant temperature is 
normal. Observe Oxygen Sensor Voltage on scanner 
under all working conditions to see if the value 
indication maintains stable around 100mV under 
some working conditions for a long time. 

No 

Diagnosis 
Instruction 

Yes 

Go to next step

3 

Connect a fuel pressure gauge to fuel inlet pipe of 
fuel system and observe fuel pressure under all 
working conditions to see if it is around 350kPa. 

No 

Check and 
repair fuel 
system 

Yes 

Repair or 
replace wire 
harness 

4 

Check respectively the connections between Pin 20 
of ECU and Pin A of sensor connector, Pin 9 of 
ECU and Pin B of sensor connector (two thin wires 
on ECU wire harness, the two thick wires are 
heating coils) to see if they are short circuit to 
ground. 

No 

Go to next step

 

21

 

Maintenance Manual for Chery·Windcloud          

Marelli EFI System 

 

5 

A.  Check intake system for severe air leakage; 
B.  Check injectors for blockage; 
C.  Check spark plug to see if clearance is proper; 
D.  Check sub live wire to see if resistance is too 

high; 

E.  Check valve clearance to see if it is proper, etc. 

Yes 

Repair as per 
diagnosis 

 

Failure: self-adaptation of air fuel ratio closed-loop control exceeds lower 

limit (too thin) 

Step Operation 

Result  Solution 

1 

Connect scanner and commutator, and then turn 
ignition switch to “ON”. 

 

Go to next step

Yes 

Go to next step

2 

Start engine and idle it until coolant temperature is 
normal. Observe Oxygen Sensor Voltage on scanner 
under all working conditions to see if the value 
indication maintains stable around 900mV under 
some working conditions for a long time. 

No 

Diagnosis 
Instruction 

Yes 

Go to next step

3 

Connect a fuel pressure gauge to fuel inlet pipe of 
fuel system and observe fuel pressure under all 
working conditions to see if it is around 350kPa. 

No 

Check and 
repair fuel 
system 

Yes 

Repair or 
replace wire 
harness 

4 

Check respectively the connections between Pin 20 
of ECU and Pin A of sensor connector, Pin 9 of 
ECU and Pin B of sensor connector (two thin wires 
on ECU wire harness, the two thick wires are 
heating coils) to see if short circuit occurs. 

No 

Go to next step

Yes 

Repair as per 
diagnosis 

5 

A.  Check injector for leakage; 
B.  Check exhaust pipe for leakage; 
C.  Check ignition timing to see if it is proper; 
D.  Check intake conduit to see if it is worn out; 
E.  Check valve clearance to see if it is proper; etc.

No 

Diagnosis 
Instruction 

 

Failure: injector circuit error in Cylinder 1 

Step Operation 

Result  Solution 

1 

Connect scanner and commutator, and then turn 
ignition switch to “ON”. 

 

Go to next step

Yes 

Go to Step 4 

2 

Unplug Cylinder 1 injector connector from wire 
harness, check the voltage between Pin 1 of the 
connector and cathode of power supply with a 
multimeter to see if it is around 12V. 

No 

Go to next step

 

22

 

Maintenance Manual for Chery·Windcloud          

Marelli EFI System 

 

Yes 

Repair or 
replace wire 
harness 

3 

Check the connection between Pin 1 of Cylinder 1 
injector connector and main relay to see if open or 
short circuit to ground occurs. 

No 

Go to next step

Yes 

Go to next step

4 

Check the resistance between Pin 1 and Pin 2 of 
Cylinder 1 injector with a multimeter to see if it is 
around 11-16Ω at 20℃. 

No 

Replace 
injector 

Yes 

Diagnosis 
Instruction 

5 

Check the voltage between Pin 2 of Cylinder 1 
injector connector and cathode of power supply 
with a multimeter to see if it is around 3.7V. 

No 

Go to next step

Yes 

Repair or 
replace wire 
harness 

6 

Check the connection between Pin 2 of Cylinder 1 
injector connector and Pin 71 of ECU to see if open, 
short circuit to power/ground occurs. 

No 

Diagnosis 
Instruction 

 

Failure: injector circuit error in Cylinder 2 

Step Operation 

Result  Solution 

1 

Connect scanner and commutator, and then turn 
ignition switch to “ON”. 

 

Go to next step

Yes 

Go to Step 4 

2 

Unplug Cylinder 2 injector connector from wire 
harness, check the voltage between Pin 1 of the 
connector and cathode of power supply with a 
multimeter to see if it is around 12V. 

No 

Go to next step

Yes 

Repair or 
replace wire 
harness 

3 

Check the connection between Pin 1 of Cylinder 2 
injector connector and main relay to see if open 
circuit or short circuit to ground occurs. 

No 

Go to next step

Yes 

Go to next step

4 

Check the resistance between Pin 1 and Pin 2 of 
Cylinder 2 injector with a multimeter to see if it is 
around 11-16Ω at 20℃. 

No 

Replace 
injector 

Yes 

Diagnosis 
Instruction 

5 

Check the voltage between Pin 2 of Cylinder 2 
injector connector and cathode of power supply 
with a multimeter to see if it is around 3.7V. 

No 

Go to next step

Yes 

Repair or 
replace wire 
harness 

6 

Check the connection between Pin 2 of Cylinder 2 
injector connector and Pin 79 of ECU to see if open, 
short circuit to power/ground occurs. 

No 

Diagnosis 
Instruction 

 
 
 

 

23