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

Euro 4 model

(B134) No. 1 — (E23) No. 4:
(B134) No. 2 — (E23) No. 4:
(B134) No. 9 — (E23) No. 4:
(B134) No. 10 — (E23) No. 4:
(B134) No. 18 — (E23) No. 3:
(B134) No. 28 — (E23) No. 1:

Euro 5 model

(B134) No. 1 — (E23) No. 4:
(B134) No. 2 — (E23) No. 4:
(B137) No. 14 — (E23) No. 1:
(B137) No. 23 — (E23) No. 3:

QUESTION

Is the resistance less than 1 Ω?

Yes No

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