DTC P0038 Ho2S Heater Control Circuit High (Bank 1 Sensor 2): Wiring Diagram

Engine electrical system, 2.5 L model (without push button start). See appropriate SYSTEM WIRING DIAGRAM article.
Engine electrical system, 2.5 L model (with push button start). See appropriate SYSTEM WIRING DIAGRAM article.

Fig 1: Heater Control - Circuit Diagram (High, Bank 1 Sensor 2)
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR. Turn the ignition switch to OFF. Measure the voltage between ECM and chassis ground. Connector & terminal (B134) No. 6 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Repair the short circuit to power in the harness between ECM and rear oxygen sensor connector.	Go to step 2 .
2 CHECK GROUND CIRCUIT FOR ECM. Disconnect the connector from ECM. Measure the resistance between ECM and chassis ground. Connector & terminal (B134) No. 3 - Chassis ground: (B134) No. 4 - Chassis ground: (B136) No. 1 - Chassis ground: (B136) No. 2 - Chassis ground: (B136) No. 3 - Chassis ground:	Is the resistance less than 5 Ω?	Repair the poor contact of ECM connector.	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