Chery A15. Manual - part 36

 

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Chery A15. Manual - part 36

 

 

 

Diagnostic trouble code: P0171 “Self adapting of closed loop control for air fuel 
ratio exceeding the upper limit” 

(Note: the following diagnostic procedures are applicable only under the 
circumstances that the trouble codes of intake air pressure sensor, carbon canister 
control valve, oxygen sensor and so on do not appear simultaneously, in case that such 
trouble codes appear at same time, overhaul shall be carried out based on the 
following procedures after dealing with other malfunctions firstly.) 

Item 

No. 

Operation procedure 

Inspection 

results 

Follow-up 

procedure 

1 

Connect the diagnostic tester and adaptor, 
and turn the ignition switch to “ON” 
position. 

 

Proceed to next 

step. 

Yes 

Proceed to next 

step. 

2 

Start up the engine, run at idle speed until 
the temperature of coolant reaches the 
normal value. 
Under the full load working condition, 
observe the value of “Oxygen sensor 
voltage” on the diagnostic tester to verify 
that the indicated value is maintained at 
100 mV without significant change for 
long time under certain working 
conditions. 

No 

Refer to diagnosis 

help. 

Yes 

Proceed to next 

step. 

3 

Connect the fuel pressure gauge to the 
feeding pipe of fuel supply system to 
observe whether the fuel pressure is 
maintained at 350kPa under full load 
working condition. 

No 

Check and repair 

the fuel system. 

Yes 

Repair and replace 

the wiring harness.

4 

Verify that the circuits between 36# and 
18# pins of ECU and A# (corresponding to 
the grey connecting wire of oxygen sensor) 
and B# (corresponding to the black 
connecting wire of oxygen sensor) pins of 
the sensor connector are short to ground. 

No 

Proceed to next 

step. 

5 

A. Verify that there is quite serious leakage 
in the air intake system; 
B. Verify that there is blockage in the fuel 
injector; 
C. Verify that the clearance of spark plug is 
excessive large; 
D. Verify that the resistance of distributor 
circuit is excessive large; 
E. Verify that the valve clearance is 
excessive large; and etc. 

Yes 

Carry out service 

based on the 

diagnostic results.

 

G-32

 

 
Diagnostic trouble code: P0172 “Self adapting of closed loop control for air fuel 
ratio exceeding the lower limit” 

(Note: The following diagnostic procedures are applicable only under the 
circumstances that the trouble codes of intake air pressure sensor, carbon canister 
control valve, oxygen sensor and so on do not appear simultaneously, in case that such 
trouble codes appear at same time, overhaul shall be carried out based on the 
following procedures after dealing with other malfunctions firstly.) 

Item 

No. 

Operation procedure 

Inspection 

results 

Follow-up 

procedure 

1 

Connect the diagnostic tester and adaptor, 
and turn the ignition switch to “ON” 
position. 

 

Proceed to next 

step. 

Yes 

Proceed to next 

step. 

2 

Start up the engine, run at idle speed until 
the temperature of coolant reaches the 
normal value. 
Under the full load working condition 
observe the value of “Oxygen sensor 
voltage” to verify that the indicated value 
is maintained at 900 mV without 
significant change for long time under 
certain working conditions. 

No 

Refer to diagnosis 

help. 

Yes 

Proceed to next 

step. 

3 

Connect the fuel pressure gauge to the 
feeding pipe of fuel supply system to 
observe whether the fuel pressure is 
maintained at 350kPa under full load 
working condition. 

No 

Check and repair 

the fuel system. 

Yes 

Repair and replace 

the wiring harness. 

4 

Verify that the circuits between 36# and 
18# pins of ECU and A# (corresponding 
to the grey connecting wire of oxygen 
sensor) and B# (corresponding to the 
black connecting wire of oxygen sensor) 
are short to power supply. 

No 

Proceed to next 

step. 

Yes 

Carry out service 

based on the 

diagnostic results. 

5 

A.  Verify that there is leakage in the fuel 
injector; 
B. Whether there is air leakage in 
exhaust pipe; 
C.  Whether the ignition timing is correct;
D.  Whether the air intake valve conduit 
is worn out; 
E. Whether the valve clearance is 
excessive small;   
And etc. 

No 

Refer to diagnosis 

help. 

 

G-33

 

Diagnostic trouble code: P0201 “Circuit malfunction of the 1 cylinder fuel 
injector” 

Item 

No. 

Operation procedure 

Inspection 

results 

Follow-up procedure

1 

Connect the diagnostic tester and adaptor, 
and turn the ignition switch to “ON” 
position. 

 

Proceed to next step.

Yes 

Proceed to Step 4 

2 

Disconnect the connector of the 1 
cylinder fuel injector on the wiring 
harness, and inspect with multimeter to 
verify that the voltage between 1# pin of 
this connector and the negative grid of 
power supply is about 12V. 

No 

Proceed to next step.

Yes 

Repair or replace the 

wiring harness. 

3 

Verify that the circuit between 1# pin of 
the connector of the 1 cylinder fuel 
injector and the main relay is open, or 
short to ground. 

No 

Proceed to next step.

Yes 

Proceed to next step.

4 

Inspect with multimeter to verify that the 
resistance between 1# and 2# pins of the 
1 cylinder fuel injector is within 11~16Ω 
under 20 .

℃

 

No 

Replace the fuel 

injector. 

Yes 

Refer to diagnosis 

help. 

5 

Inspect with multimeter to verify that the 
voltage between the connector of the 1 
cylinder fuel injector (2# pin) and the 
negative grid of power supply is about 
3.7V. 

No 

Proceed to next step.

Yes 

Repair and replace 

the wiring harness. 

6 

Verify that the circuit between the 
connector of the 1 cylinder fuel injector 
(2# pin) and 27# pin of ECU is open or 
short to ground or power supply. 

No 

Refer to diagnosis 

help. 

 

 

G-34

 

Diagnostic trouble code: P0202 “Circuit malfunction of the double cylinder fuel 
injector” 

Item 

No. 

Operation procedure 

Inspection 

results 

Follow-up 

procedure 

1 

Connect the diagnostic tester and adaptor, 
and turn the ignition switch to “ON” 
position. 

 

Proceed to next 

step. 

Yes 

Proceed to Step 4 

2 

Disconnect the connector of the double 
cylinder fuel injector on the wiring 
harness, and inspect with multimeter to 
verify that the voltage between 1# pin of 
this connector and the negative grid of 
power supply is about 12V. 

No 

Proceed to next 

step. 

Yes 

Repair and replace 

the wiring harness.

3 

Verify that the circuit between 1# pin of 
the connector of the double cylinder fuel 
injector and the main relay is open, or 
short to ground. 

No 

Proceed to next 

step. 

Yes 

Proceed to next 

step. 

4 

Inspect with multimeter to verify that the 
resistance between 1# and 2# pins of the 
double cylinder fuel injector is within 
11~16Ω under 20 .

℃

 

No 

Replace the fuel 

injector. 

Yes 

Refer to diagnosis 

help. 

5 

Inspect with multimeter to verify that the 
voltage between the connector of the 
double cylinder fuel injector (2# pin) and 
the negative grid of power supply is about 
3.7V. 

No 

Proceed to next 

step. 

Yes 

Repair or replace 

the wiring harness.

6 

Verify that the circuit between the 
connector of the double cylinder fuel 
injector (2# pin) and 6# pin of ECU is 
open or short to ground or power supply. 

No 

Refer to diagnosis 

help. 

 
 

 

 

 

 

 

 

 

 

G-35

 

 

 

 

 

 

 

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