DTC P0141: O2 Sensor Heater Circuit (Bank 1 Sensor 2): Wiring Diagram

Engine electrical system turbo engine model (without push button start) < Ref. to TURBO MODEL (WITHOUT PUSH BUTTON START) , WIRING DIAGRAM, Engine Electrical System. >
Engine electrical system turbo engine model (with push button start) < Ref. to TURBO MODEL (WITH PUSH BUTTON START) , WIRING DIAGRAM, Engine Electrical System. >

Fig 1: Rear Oxygen Sensor Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DTC PROCEDURE

Step	Check	Yes	No
1 CHECK POWER SUPPLY TO REAR OXYGEN SENSOR. Turn the ignition switch to OFF. Disconnect the connector from rear oxygen sensor. Turn the ignition switch to ON. Measure the voltage between rear oxygen sensor connector and engine ground. Connector & terminal (E25) No. 1 (+) - Engine ground (-):	Is the voltage 10 V or more?	Go to step 2 .	Repair the power supply line. NOTE: In this case, repair the following item: Open circuit in harness between A/F, oxygen sensor relay and rear oxygen sensor connector Poor contact of A/F, oxygen sensor relay connector Poor contact of coupling connector Malfunction of A/F, oxygen sensor relay
2 CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR. Turn the ignition switch to OFF. Disconnect the connector from ECM. Measure the resistance between the ECM and rear oxygen sensor connector. Connector & terminal (E25) No. 2 - (E159) No. 3:	Is the resistance less than 1 Ω?	Go to step 3 .	Repair the open circuit of harness between ECM and rear oxygen sensor connector.
3 CHECK GROUND CIRCUIT FOR ECM. Measure the resistance of harness between ECM and engine ground. Connector & terminal (B134) No. 35 - Engine ground: (B134) No. 47 - Engine ground: (E159) No. 10 - Engine ground: (E159) No. 17 - Engine ground: (E159) No. 18 - Engine ground: (E159) No. 25 - Engine ground: (E159) No. 26 - Engine ground:	Is the resistance less than 5 Ω?	Go to step 4 .	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit of harness between ECM and engine ground Poor contact of coupling connector
4 CHECK REAR OXYGEN SENSOR. Measure the resistance between rear oxygen sensor connector terminals. Terminals No. 1 - No. 2:	Is the resistance 5.4 - 7.3 Ω?	Repair the poor contact of ECM connector.	Replace the rear oxygen sensor. < Ref. to REAR OXYGEN SENSOR . >