Engine Electrical System

Diagnostic trouble code: P0134 “Signal malfunction of upstream oxygen sensor”
(Note: The following diagnostic procedures are applicable only under the
circumstances that the trouble code of P0135 does not appear simultaneously, in case
that such trouble code appears at the same time, overhaul shall be carried out based on
the following procedures after dealing with the malfunction of P0135 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
Refer to diagnosis
help.
2
Start up the engine, run at idle speed until
the temperature of coolant reaches the
normal value. Observe the value of
“Oxygen sensor voltage” on the diagnostic
tester to verify that the indicated value is
changed quickly within the range of
100mV – 900mV.
No
Proceed to next
step.
Yes
Repair and replace
the wiring
harness.
3
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 open.
No
Refer to diagnosis
help.
E-30
PDF created with pdfFactory Pro trial version www.pdffactory.com