Mitsubishi FUEL Manual page 20

13A-20
Code No. P0125 Feedback system
Range of Check
D The engine coolant temperature is approx. 80_C or more.
D During stoichiometric feedback control
D The vehicle is not being decelerated.
Set Conditions
D Oxygen sensor (front) output voltage has been higher or lower than 0.5 V for
at least thirty seconds.
Check the following connector:
C-46
OK
Measure at oxygen sensor (front)
connector C-46.
D Disconnect the connector and
measure at the harness side.
D Resistance between terminal 2
and earth
OK: 2 W or less
OK
Measure at oxygen sensor (front)
connector C-46.
D Measure the voltage at the
oxygen sensor (front) terminal
D Engine: 2,500 r/min (after
warming up)
(1) Voltage between terminal 2 and
earth
OK: 0.5 V or less
(2) Voltage between terminal 1 and
earth
OK: 0 V and 0.8 V alternate.
OK
Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-175 <A/T>.
D Measure the voltage at the
engine-ECU terminal <M/T> or
engine-A/T-ECU terminal <A/T>.
D Engine: 2,500 r/min (after
warming up)
D Voltage between terminal 76
<M/T>, 71 <A/T> and earth
OK: 0 V and 0.8 V alternate.
OK
Check the following connector:
C-40 <M/T>, C-175 <A/T>
OK
Check the trouble symptoms.
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
MPI <4G6> -
NG
Repair
NG
Check the following connector:
C-40 <M/T>, C-176 <A/T>
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
Check the trouble symptoms.
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
(1) NG
Check the following connector:
C-40 <M/T>, C-176 <A/T>
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
(2) NG
Check the oxygen sensor (front).
(Refer to P.13A-89.)
Check the following connector:
C-40 <M/T>, C-175 <A/T>
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
NG
Check the following connector:
C-40 <M/T>, C-175 <A/T>
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
NG
Repair
OK
Transient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
Troubleshooting
Probable cause
D Malfunction of oxygen sensor (front)
D Open or short circuit in the oxygen sensor (front)
circuit or loose connector contact
D Malfunction of engine-ECU <M/T>
D Malfunction of engine-A/T-ECU <A/T>
NG
OK
NG
OK
NG
NG
OK
NG
OK
NG
OK
NG
OK
Repair
Repair
Repair
Replace
Repair
Repair