DTC P0141 O2 Sensor Heater Circuit (Bank1 Sensor2): Wiring Diagram

Engine Electrical System ENGINE TYPE FA (WITHOUT PUSH BUTTON START) <Ref. to 2.0L TURBO (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>
Engine Electrical System ENGINE TYPE FA (WITH PUSH BUTTON START) <Ref. to 2.0L TURBO (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Fig 1: O2 Sensor Heater Circuit Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC 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 ECM connector 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 connector and rear oxygen sensor connector.
3 CHECK GROUND CIRCUIT FOR ECM. Measure the resistance of harness between ECM connector 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 connector 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 .>