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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 Refer to ENGINE (DIAGNOSTICS) (STI)>CLEAR MEMORY MODE>OPERATION ., and inspection mode Refer to ENGINE (DIAGNOSTICS) (STI)>INSPECTION MODE>PROCEDURE .

Wiring diagram:

Engine Electrical System Refer to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .

G12456917

Courtesy of SUBARU OF AMERICA, INC.

CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR.
1. Start and warm up the engine.
2. Turn the ignition switch to OFF.
3. Disconnect the connector from ECM.
4. Check the front oxygen (A/F) sensor. Refer to INSPECTION .
Is the check result OK?

Yes: Go to 2.

No: Repair the open circuit of harness between ECM connector and front oxygen (A/F) sensor connector.
CHECK FRONT OXYGEN (A/F) SENSOR.
Check the front oxygen (A/F) sensor. Refer to INSPECTION .

Is the check result OK?

Yes: Go to 3.

No: Replace the front oxygen (A/F) sensor. Refer to FUEL INJECTION (FUEL SYSTEMS) (STI)>FRONT OXYGEN (A/F) SENSOR .
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?

Yes: Repair the poor contact of ECM or front oxygen (A/F) sensor connector.

No: Replace the front oxygen (A/F) sensor. Refer to FUEL INJECTION (FUEL SYSTEMS) (STI)>FRONT OXYGEN (A/F) SENSOR .