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.
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

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

Fig 1: A/F And O2 Heater Control Circuit High 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 (E158) No. 10 (+) - 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 (E158) No. 61 - Chassis ground: (E158) No. 62 - Chassis ground: (E158) No. 63 - Chassis ground: (E158) No. 64 - Chassis ground: (E158) No. 65 - Chassis ground:	Is the resistance less than 5 Ω?	Repair the poor contact of ECM connector.	Repair the open circuit in harness between ECM connector and engine ground.