Great Wall GW491QE, Service Manual

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EF.1-65
S.N. Operation steps
Check
result
Follow-up steps
Yes
Repair or change the wiring
harness. 5
Check whether the loop between the control end (i.e. Pin 86 ) of
air-conditioner compressor relay and Pin 70 of ECU is a broken loop.
No Next step.
Yes Diagnosis help.
6
Check whether the electromagnetic clutch for air-conditioner compressor is
working in a normal way.
No
Repair or change the
electromagnetic clutch.
Fault code
：
P0646 The voltage in the control loop of air-conditioner compressor relay is too low.
”
S.N. Operation steps
Check
result
Follow-up steps
1
Connect with a diagnosis instrument, and place the ignition switch to the
OFF
”
position.
Next step.
Yes
Continue to proceed until
step 4.
2
Pull out the relay from the air-conditioner compressor, place the ignition
switch to the ON
”
position, and verify the voltage between the power supply
end (ie. Pin 30 &85 ) of relay and the negative electrode of power supply is
about 12V.
No Next step.
Yes
Repair or change the wiring
harness.
3
Check whether the loop on the power supply end of relay is a broken loop or
short circuit to ground.
No
Continue to proceed until
step 2.
Yes Change the relay.
4
A multimeter may be used to verify the voltage between the control end (i.e.
Pin 86 of relay) of air-conditioner compressor relay and the negative electrode
of power supply is about 3.7V.
No Next step.
Yes
Repair or change the wiring
harness. 5
Check whether the loop between the control end (ie. Pin 86) of air-conditioner
compressor relay and Pin 70 of ECU is a broken loop.
No
Next step.
Yes
Diagnosis help.
6
Check whether the electromagnetic clutch for air-conditioner compressor is
working in a normal way.
No
Repair or change the
electromagnetic clutch.
Fault code
：
P0647 The voltage in the control loop of air-conditioner compressor relay is too high.
”
S.N. Operation steps
Check
result
Follow-up steps
1
Connect with a diagnosis instrument, and place the ignition switch to the
OFF
”
position.
Next step.
Yes
Continue to proceed until
step 4.
2
Pull out the relay from the air-conditioner compressor, place the ignition
switch to the ON
”
position, and verify the voltage between the power supply
end (ie. Pin 30 &85 ) of relay and the negative electrode of power supply is
about 12V.
No Next step.
Yes
Repair or change the wiring
harness.
3
Check whether the loop on the power supply end of relay is a broken loop or
short circuit to ground.
No
Continue to proceed until
step 2.
Yes Change the relay.
4
A multimeter may be used to verify the voltage between the control end (i.e.
Pin 86 of relay) of air-conditioner compressor relay and the negative electrode
of power supply is about 3.7V.
No
Next step.
Yes
Repair or change the wiring
harness. 5
Check whether the loop between the control end (i.e. Pin 86 of relay) of
air-conditioner compressor relay and Pin 70 of ECU is short circuit to power
supply. No
Next step.
Yes Diagnosis help.
6
Check whether the electromagnetic clutch for air-conditioner compressor is
working in a normal way.
No
Repair or change the
electromagnetic clutch.
M7.9.7 system service &diagnosis flow process based on fault code
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