Engine Electrical System

Diagnostic trouble code: P0135 “Malfunction in heating circuit of upstream
oxygen sensor”
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
Disconnect the connector of the oxygen
sensor on the wiring harness and inspect
with multimeter to verify that the voltage
between C# (corresponding to the white
connecting wire of the oxygen sensor)
and D# (corresponding to the white
connecting wire of the oxygen sensor)
pins of this connector is about 12V.
No Proceed to Step4
Yes
Proceed to next
step.
3
Inspect with multimeter to verify that the
resistance between C# (white) and D#
(white) pins of the oxygen sensor is
within 1~6Ω under 20.℃
No Replace the sensor.
Yes Replace the fuse.
4
Verify that the 8A fuse in heating circuit
of the oxygen sensor is burn out.
No
Proceed to next
step.
Yes
Repair and replace
the wiring harness.
5
Verify that the circuits between 1# pin of
ECU, 87# pin of the main relay and C#
(corresponding to white connecting wire
of the oxygen sensor) and D#
(corresponding to white connecting wire
of the oxygen sensor) are open or short to
ground or power supply.
No
Refer to diagnosis
help.
E-31
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