Chery A21 2005, Service Manual, Page: 360 / 475

CHERY
·
A21 SERVICE MANUAL ENGINE EFI SYSTEM
37
No. Operating steps Result Follow up steps
1
Connect the diagnostic tester and commutator, put the
ignition switch to
“
ON
”
.
Next step
Yes Diagnosis help
2
Start the engine and leave it at idle speed until its
coolant reaches to the normal value. Observe the value
changes of
“
oxygen sensor voltage
”
item on diagnostic
meter, the displayed value should change rapidly from
100mV-900mV.
No Next step
Yes
Repair or change
cable
3
Check if there is short circuit to power supply between
pin No.36, No.18, of ECU and pin A (opposite to
oxygen sensor gray connecting line), B (opposite to
oxygen sensor black connecting line).
No Diagnosis help
Yes
Check and repair
according to
diagnosis
4
A, check if the exhaust system is jammed
B, check if the injector is leaking
C, check if the fuel pressure is over higher
D, check if the valve clearance is over smaller etc. No Diagnosis help
DTC: P0134 Signal failure of upstream oxygen sensor
(Notice: below diagnosis process is fit for those without P0135 at the same time; if there is
P0135 failure, please deal with P0135 failure at first and then check as below.)
No. Operating steps Result Follow up steps
1
Connect the diagnostic tester and commutator, put the
ignition switch to
“
ON
”
.
Next step
Yes Diagnosis help
2
Start the engine and leave it at idle speed until its
coolant temperature reaches to the normal value.
Observe the value changes of
“
oxygen sensor voltage
”
item on diagnostic meter, the displayed value should
change rapidly from 100mV-900mV.
No Next step
Yes
Repair or change
cable
3
Check if there is open circuit between pin No.36,
No.18, of ECU and pin A (opposite to oxygen sensor
gray connecting line), B (opposite to oxygen sensor
black connecting line) of sensor joint.
No Diagnosis help
DTC: P0135 Heating circuit failure of upstream oxygen sensor
No. Operating steps Result Follow up steps
1
Connect the diagnostic tester and commutator, put the
ignition switch to
“
ON
”
.
Next step
Yes Next step
2
Take off the oxygen sensor joint on the cable and
check the voltage between the pins of C (opposite to
oxygen sensor white connecting line) and D (opposite
to oxygen sensor white connecting line) by multimeter,
and observe if it is about 12V.
No To step No.4
3 Check the resistance value between oxygen sensor Yes Next step
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