DTC P0030 A/F/O2 Heater Control Circuit Bank 1 Sensor 1: 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/O2 Heater Control Circuit Low Bank 1 Sensor 1 - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR. Start and warm up the engine. Turn the ignition switch to OFF. Disconnect the connector from ECM. Disconnect the connectors from front oxygen (A/F) sensor. Measure the resistance of harness between ECM connector and front oxygen (A/F) sensor connector. Connector & terminal (E158) No. 15 - (E24) No. 1: (E159) No. 9 - (E24) No. 2: (E158) No. 27 - (E24) No. 4: (E158) No. 39 - (E24) No. 5:	Is the resistance less than 1 Ω?	Go to step 2 .	Repair the open circuit of harness between ECM connector and front oxygen (A/F) sensor connector.
2 CHECK FRONT OXYGEN (A/F) SENSOR. Measure the resistance between front oxygen (A/F) sensor terminals. Terminals No. 2 - No. 3:	Is the resistance 2 - 3 Ω?	Go to step 3 .	Replace the front oxygen (A/F) sensor. <Ref. to Front Oxygen (A/F) Sensor .>
3 CHECK FOR POOR CONTACT. Check for poor contact of ECM and front oxygen (A/F) sensor connector.	Is there poor contact of ECM or front oxygen (A/F) sensor connector?	Repair the poor contact of ECM or front oxygen (A/F) sensor connector.	Replace the front oxygen (A/F) sensor. <Ref. to Front Oxygen (A/F) Sensor .>