ENGINE (DIAGNOSTICS)(H4DO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0030 HO2S HEATER CONTROL CIRCUIT (BANK 1 SENSOR 1)

ENGINE (DIAGNOSTICS)(H4DO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P0030 HO2S HEATER CONTROL CIRCUIT (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

Two consecutive driving cycles with fault

CAUTION:

After repairing or replacing the defective part, perform the Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

STEP	CHECK	YES	NO
1.CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR. 1) Start and warm-up engine. 2) Turn the ignition switch to OFF. 3) Disconnect the connectors from ECM and front oxygen (A/F) sensor. 4) Measure the resistance of harness between ECM and front oxygen (A/F) sensor connector. Connector & terminal (B134) No. 1 — (E23) No. 4: (B134) No. 2 — (E23) No. 4: (B134) No. 9 — (E23) No. 4: (B134) No. 10 — (E23) No. 4:	Is the resistance less than 1 Ω?		Repair the open circuit of 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. 28 — (E23) No. 1: (B134) No. 18 — (E23) No. 3:	Is the resistance less than 1 Ω?		Repair the open circuit of 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 — (E23) No. 6:	Is the resistance less than 1 Ω?		Repair the open circuit of 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. 6 — No. 4:	Is the resistance less than 5 Ω?		Replace the front oxygen (A/F) sensor.
5.CHECK POOR CONTACT. Check the poor contact of ECM and front oxygen (A/F) sensor connector.	Is there poor contact in the ECM or front oxygen (A/F) sensor connector?	Repair poor contact of the ECM or front oxygen (A/F) sensor.	Replace the front oxygen (A/F) sensor.