DTC P0030 Ho2S Heater Control Circuit (Bank 1 Sensor 1)

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

DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
GENERAL DESCRIPTION < Ref. to DTC P0030 HO2S HEATER CONTROL CIRCUIT (BANK 1 SENSOR 1) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

CAUTION: After repair or replacement of faulty parts, conduct Clear Memory Mode < Ref. to , OPERATION , Clear Memory Mode.> and Inspection Mode < Ref. to , PROCEDURE , Inspection Mode.>.

WIRING DIAGRAM:

Fig 1: Wiring Diagram - DTC P0030 Ho2S Heater Control Circuit (Bank 1 Sensor 1)

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE (DTC P0030)

Step	Check	Yes	No
1 CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR. Start the engine and warm-up engine. Turn the ignition switch to OFF. Disconnect the connectors from ECM and front oxygen (A/F) sensor. Measure the resistance of harness between ECM and front oxygen (A/F) sensor connector. Connector & terminal (B134) No. 2 - (B18) No. 1: B134 No. 3 - (B18) No. 1:	Is the resistance less than 1 ?	Go to step 2.	Repair the open circuit in harness between ECM and front oxygen (A/F) sensor connector.
2 CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR. Measure the resistance of harness between ECM and front oxygen (A/F) sensor connector. Connector & terminal (B134) No. 26 - (B18) No. 4: (B134) No. 33 - (B18) No. 3:	Is the resistance less than 1 ?	Go to step 3.	Repair the open circuit in harness between ECM and front oxygen (A/F) sensor connector.
3 CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR. Measure the resistance of harness between main relay and front oxygen (A/F) sensor connector. Connector & terminal (B47) No. 3 - (B18) No. 2:	Is the resistance less than 1 ?	Go to step 4.	Repair the open circuit in harness between ECM and front oxygen (A/F) sensor connector.
4 CHECK FRONT OXYGEN (A/F) SENSOR. Measure the resistance between front oxygen (A/F) sensor connector terminals. Terminals No. 1 - No. 2:	Is the resistance less than 5 ?	Go to step 5.	Replace the front oxygen (A/F) sensor. < Ref. to FRONT OXYGEN (A/F) SENSOR . >
5 CHECK POOR CONTACT. Check the poor contact in ECM and front oxygen (A/F) sensor connector.	Is there poor contact in ECM or front oxygen (A/F) sensor connector?	Repair the poor contact in ECM or front oxygen (A/F) sensor connector.	Replace the front oxygen (A/F) sensor. < Ref. to FRONT OXYGEN (A/F) SENSOR . >