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M/T

DTC P0141 - REAR OXYGEN SENSOR HEATER CIRCUIT LOW INPUT

DTC DETECTING CONDITION:
- Two consecutive driving cycles with fault

CAUTION: After repair or replacement of faulty parts, conduct CLEAR MEMORY MODE and INSPECTION MODE. Refer to How To Clear Diagnostic Trouble Codes.

Wiring Diagram:





WIRING DIAGRAM

10S1: CHECK ANY OTHER DTC ON DISPLAY.

CHECK: Does the Subaru Select Monitor or OBD-II general scan tool indicate DTC P0141 and P0135 at the same time?

YES: Go to step 10S2.

NO: Go to step 10S3.

10S2: CHECK GROUND CIRCUIT OF ECM.

1. Turn ignition switch to OFF.
2. Disconnect connector from ECM.

Connector & Terminal - [(B134) No.35 - Chassis Ground]:





3. Measure resistance of harness between ECM connector and chassis ground.

CHECK: Is the resistance less than 10 Ohms?

YES: Go to step 10S4.

NO: Go to step 10S3.

10S3: CHECK GROUND CIRCUIT OF ECM.

1. Repair harness and connector.

NOTE: In this case, repair the following:
- Open circuit in harness between ECM and engine ground terminal
- Poor contact in ECM connector
- Poor contact in coupling connector (B22)

Connector & Terminal - [(B134) No.34 - Chassis Ground]:





2. Measure resistance of harness between ECM connector and chassis ground.

CHECK: Is the resistance less than 5 Ohms?

YES: Go to step 10S4.

NO: Repair harness and connector.

NOTE: In the is case, repair the following:
- Open circuit in harness between ECM and engine ground terminal
- Poor contact in ECM connector Poor contact in coupling connector (B22)

10S4: CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR.

Connector & Terminal - [(B134) No.21 - Chassis Ground]:





Measure resistance of harness between ECM connector and chassis ground.

CHECK: Is the resistance less than 10 Ohms?

YES: Repair ground short circuit in harness between ECM and rear oxygen sensor connector.

NO: Go to step 10S5.

10S5: CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR.

1. Disconnect connector from rear oxygen sensor.

Connector & Terminal - [(B134 No.21 - (T6) No.4]:





2. Measure resistance of harness between ECM and rear oxygen sensor connector.

CHECK: Is the resistance less than 3 Ohms?

YES: Go to step 1086.

NO: Repair open circuit in harness between ECM and rear oxygen sensor connector.

10S6: CHECK POWER SUPPLY TO REAR OXYGEN SENSOR.

1. Connect connector to ECM.
2. Turn ignition switch to ON.

Connector & Terminal - [(T6) No.2 (+) - Engine Ground (-)]:





3. Measure voltage between rear oxygen sensor connector and engine ground or chassis ground.

CHECK: Is the voltage more than 10 V?

YES: Go to step 10S7.

NO: Repair power supply line.

NOTE: In this case, repair the following:
- Open circuit in harness between main relay and rear oxygen sensor connector
- Poor contact in rear oxygen sensor connector
- Poor contact in coupling connector (T5)

110S7: CHECK REAR OXYGEN SENSOR.

1. Turn ignition switch to OFF.

Terminals - [No.2 - No.4]:





2. Measure resistance between rear oxygen sensor connector terminals.

CHECK: Is the resistance less than 30 Ohms?

YES: Repair harness and connector.

NOTE: In this case, repair the following:
- Open circuit in harness between rear oxygen sensor and ECM connector
- Poor contact in rear oxygen sensor connector
- Poor contact in ECM connector
- Poor contact in coupling connector (T5)

NO: Replace rear oxygen sensor.