P0141
DTC P0141 - REAR OXYGEN SENSOR HEATER CIRCUIT MALFUNCTIONDTC 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
11R1: 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 5 ohm?
YES: Go to step 11R3.
NO: Go to step 11R2.
11R2: 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 ohm?
YES: Go to step 11R3.
NO: 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).
11R3: CHECK CURRENT DATA.
1. Start engine.
2. Read data of rear oxygen sensor heater current using Subaru Select Monitor or OBD-II general scan tool.
NOTE:
- Subaru Select Monitor
For detailed operation procedure, refer to the "READ CURRENT DATA SHOWN ON DISPLAY FOR ENGINE". Refer to Normal Scan Data Values.
- OBD-II scan tool
For detailed operation procedures, refer to the OBD-II General Scan Tool Instruction Manual.
CHECK: Is the value more than 0.2 A?
YES: Repair connector.
NOTE: In this case, repair the following:
- Poor contact in rear oxygen sensor connector.
- Poor contact in rear oxygen sensor connecting harness connector.
- Poor contact in ECM connector
NO: Go to step 11R4.
11R4: CHECK OUTPUT SIGNAL FROM ECM.
1. Start and idle the engine.
Connector & terminal (B134) No.21 (+) - Chassis ground (-):
2. Measure voltage between ECM connector and chassis ground.
CHECK: Is the voltage less than 1.0 Volt?
YES: Go to step 11R7.
NO: Go to step 11R5.
11R5: CHECK OUTPUT SIGNAL FROM ECM.
Connector & terminal (B134) No.21 (+) - Chassis ground (-):
Measure voltage between ECM connector and chassis ground
CHECK: Does the voltage change less than 1.0 Volt by shaking harness and connector of ECM while monitoring the value with voltage meter?
YES: Repair poor contact in ECM connector.
NO: Go to step 11R6.
11R6: CHECK OUTPUT SIGNAL FROM ECM.
1. Disconnect connector from rear oxygen sensor.
Connector & terminal (B134) No.21 (+) - Chassis ground (-):
2. Measure voltage between ECM connector and chassis ground.
CHECK: Is the voltage less than 1.0 Volt?
YES: Replace ECM.
NO: Repair battery short circuit in harness between ECM and rear oxygen sensor connector. After repair, replace ECM.
11R7: CHECK POWER SUPPLY TO REAR OXYGEN SENSOR.
1. Turn ignition switch to OFF.
2. Disconnect connector from rear oxygen sensor.
3. Turn ignition switch to ON.
Connector & terminal (E25) No.2 (+) - Chassis ground (-):
4. Measure voltage between rear oxygen sensor connector and engine ground or chassis ground.
CHECK: Is the voltage more than 10 Volt?
YES: Go to step 11R8.
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 (E1).
11R8: CHECK REAR OXYGEN SENSOR.
1. Turn ignition switch to OFF.
Terminals No 1 - No.2:
2. Measure resistance between rear oxygen sensor connector terminals.
CHECK: Is the resistance less than 30 ohm?
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 (E1).
NO: Replace rear oxygen sensor.