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

DTC P0131 O2 SENSOR CIRCUIT LOW VOLTAGE (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

Immediately at fault recognition

CAUTION:

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

WIRING DIAGRAM:

STEPCHECKYESNO

1.CHECK FRONT OXYGEN (A/F) SENSOR CONNECTOR AND COUPLING CONNECTOR.

Has water entered the connector?

Completely remove any water inside.

2.CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the ECM and front oxygen (A/F) sensor.

3) Measure the resistance of harness between ECM and front oxygen (A/F) sensor connector.

Connector & terminal

(B137) No. 23 — (E23) No. 3:

(B137) No. 14 — (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 FOR POOR CONTACT.

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

Is there poor contact in front oxygen (A/F) sensor connector?

Repair the poor contact of the front oxygen (A/F) sensor connector.

Replace the front oxygen (A/F) sensor.