DTC P0030: A/F/O2 Heater Control Circuit Bank 1 Sensor 1: Notes

WARNING: This page is about a different variant/trim than selected.

1. -

DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>ENGINE ELECTRICAL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR (OPEN) .
1. Turn the ignition switch to ON.
2. Navigate to Inspection Mode for measuring Exhaust Gas. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>WORK SUPPORT>OPERATION>SERVICE MODE .
  NOTE: If it is necessary to run the engine for 10 minutes or more, fasten the driver's seat belt.
3. Start and warm up the engine.
4. Turn the ignition switch to OFF.
5. Disconnect the connector from ECM.
6. Disconnect the connector from the front oxygen (A/F) sensor.
7. Measure the resistance of harness between ECM connector and front oxygen (A/F) sensor connector.
Connector and terminal

(E158) No. 88 - (B379) No. 1:

(E158) No. 3 - (B379) No. 3:

(E158) No. 4 - (B379) No. 4:

Is the resistance less than 1 Ω?

Yes: Go to 2.

No: Check the harnesses and connectors, and repair or replace them if necessary.
NOTE:
In this case, repair the following item:
- Open circuit in harness between ECM connector and front oxygen (A/F) sensor connector
- Poor contact of coupling connector
CHECK FRONT OXYGEN (A/F) SENSOR .
Check the front oxygen (A/F) sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO(HEV))>FRONT OXYGEN (A/F) SENSOR>INSPECTION .

Is the check result OK?

Yes: Go to 3.

No: Replace the front oxygen (A/F) sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO(HEV))>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. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO(HEV))>FRONT OXYGEN (A/F) SENSOR .