DTC P0141: O2 Sensor Heater Circuit Bank 1 Sensor 2: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

Failure detection pattern: 

• "Primary" (high-priority diagnosis)

Warning light/indicator light: 

• Malfunction indicator light◦

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM>2.0 L MODEL .

Courtesy of SUBARU OF AMERICA, INC.

1. BASIC INSPECTION  .

   Before performing the diagnosis, perform basic inspection. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0)>GENERAL DESCRIPTION>INSPECTION .

   NOTE:

   • Check the battery and its installation condition.
   • Check the related fuse.
   • Visually check that the related connectors are properly connected.

     Also, check the related ground terminal for looseness and corrosion.

   Is the check result OK?

   Yes  : GO TO  2.

   No  : Repair the defective part.

   After the repair, GO TO  6.

2. CHECK REAR OXYGEN SENSOR POWER SUPPLY  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the rear oxygen sensor.
      CAUTION: When disconnecting the connector, check for poor contact due to damage, looseness, adherence of foreign matter on the connector and terminal.
   3. Turn the ignition switch to ON. (Engine OFF)
   4. Measure the voltage between the following terminals.

      Connector & terminal: Standard 

      (B95) No. 1 (+) - Chassis ground (-): 11 V - 14 V

   Is the check result OK?

   Yes  : GO TO  3.

   No  : Repair the defective part.

   NOTE: Repair the following item.

   • Open circuit or short circuit to ground in harness between M/B and rear oxygen sensor connector
   • Blown out of fuse
   • Poor contact of coupling connector

   After the repair, GO TO  6.

3. CHECK HARNESS (SHORT TO GROUND IN REAR OXYGEN SENSOR)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from ECM.
      CAUTION: When disconnecting the connector, check for poor contact due to damage, looseness, adherence of foreign matter on the connector and terminal.
   3. Measure the resistance between the following terminals.

      Connector & terminal: Standard 

      (B95) No. 2 - Chassis ground: 10 KΩ or more

   Is the check result OK?

   Yes  : GO TO  4.

   No  : Repair the defective part.

   After the repair, SGO TO  6.

4. CHECK HARNESS (OPEN CIRCUIT BETWEEN ECM CONNECTOR AND ENGINE GROUND)  .

   Measure the resistance between the following terminals.

   Connector & terminal: Standard 

   (B62) No. 69 - Chassis ground: Less than 5 Ω

   (B62) No. 70 - Chassis ground: Less than 5 Ω

   (B62) No. 71 - Chassis ground: Less than 5 Ω

   (B62) No. 72 - Chassis ground: Less than 5 Ω

   Is the check result OK?

   Yes  : GO TO  5.

   No  : Repair the defective part.

   NOTE: Repair the following item.

   • Open circuit of harness between ECM connector and engine ground
   • Poor contact of coupling connector

   After the repair, GO TO  6.

5. CHECK REAR OXYGEN SENSOR  .

   Check the rear oxygen sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>REAR OXYGEN SENSOR>INSPECTION .

   CAUTION: If water has entered the connector, remove it.

   Is the check result OK?

   Yes  : Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM) .

   After replacement, GO TO  6.

   No  : Replace the rear oxygen sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>REAR OXYGEN SENSOR .

   After replacement, GO TO  6.

6. CHECK REPAIR  .
   1. Perform the inspection mode corresponding to DTC. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0)>INSPECTION MODE>PROCEDURE .
   2. Confirm that DTC or cancel code is not stored and the malfunction is eliminated.

   Is the check result OK?

   Yes  : Finish the diagnosis.

   No  : Perform the diagnosis according to the basic diagnostic procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .