DTC P0038 A/F/O2 Heater Control Circuit High Bank 1 Sensor 2: Notes

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

CAUTION: After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to OPERATION , Clear Memory Mode.>, and Inspection Mode <Ref. to PROCEDURE , Inspection Mode.>.

WIRING DIAGRAM:

Engine Electrical System <Ref. to WIRING DIAGRAM , Engine Electrical System.>

Fig 1: A/F/O2 Heater Control Circuit Low Bank 1 Sensor 2 Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

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 connector and chassis ground. Connector & terminal (B135) No. 6 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Repair the short circuit to power in the harness between ECM connector 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 connector and chassis ground. Connector & terminal (B134) No. 3 - Chassis ground: (B134) No. 4 - Chassis ground: (B134) No. 6 - Chassis ground: (B137) No. 1 - Chassis ground: (B137) 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 connector and engine ground Poor contact of coupling connector