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

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

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

STEPCHECKYESNO

1.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 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 harness and connector.

NOTE:

In this case, repair the following item:

• Open circuit in harness between ECM and front oxygen (A/F) sensor connector

• Poor contact of coupling 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. 18 — (E23) No. 3:

(B134) No. 28 — (E23) No. 1:

Is the resistance less than 1 Ω?

Repair the harness and connector.

NOTE:

In this case, repair the following item:

• Open circuit in harness between ECM and front oxygen (A/F) sensor connector

• Poor contact of coupling connector

3.CHECK FRONT OXYGEN (A/F) SENSOR.

Measure the resistance between front oxygen (A/F) sensor terminals.

Terminals

No. 4 — No. 6:

Is the resistance 1 Ω?

Replace the front oxygen (A/F) sensor.

4.CHECK POOR CONTACT.

Check for poor contact of 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 of ECM or front oxygen (A/F) sensor connector.

Replace the front oxygen (A/F) sensor.