MPI <4G1> -
Troubleshooting
13A-21
Code No. P0135 Oxygen sensor heater (front) system
<sensor 1>
Probable cause
Range of Check
D
The engine coolant temperature is approx. 20
_
C or more.
D
The oxygen sensor heater (front) remains on.
D
The engine speed is 50 r/min or more.
D
Battery voltage is 11 - 16 V.
Set Conditions
D
The current, which flows through the oxygen sensor heater (front), is 0.2 A
or less or 3.5 A or more for six seconds.
D
Malfunction of oxygen sensor heater (front)
D
Open or short circuit in the oxygen sensor heater
(front) circuit or loose connector contact
D
Malfunction of engine-ECU
OK
Replace the engine-ECU.
NG
Replace the engine-ECU.
OK
Check the trouble symptoms.
OK
Transient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
OK
Check the harness wires between
the oxygen sensor (front) and the
engine-ECU and between the oxygen
sensor (front) and the engine control
relay.
NG
Repair
OK
Check the following connector:
B-35
NG
Repair
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU.
Repair
NG
Check the following connector:
B-35
NG
OK
Measure at engine-ECU connector
B-35.
D
Measure the voltage at the
engine-ECU terminal.
D
Ignition switch: ON
D
Voltage between terminal 60 and
earth
OK:
System voltage
OK
Check the harness wires between
the oxygen sensor (front) and the
engine control relay, and repair if
necessary.
Repair
NG
Check the following connector:
B-13
NG
OK
Measure at oxygen sensor (front)
connector A-106.
D
Disconnect the connector and
measure at the harness side.
D
Ignition switch: ON
D
Voltage between terminal 1 and
earth
OK:
System voltage
OK
Check the following connector:
A-106
NG
Repair
Measure at oxygen sensor (front)
connector A-106.
D
Disconnect the connector and
measure at the harness side.
D
Resistance between terminals 1
and 3
OK:
4.5 - 8.0
W
NG
Replace
Repair
NG