CHECK OUTPUT SIGNAL OF ECM.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the rear oxygen sensor.

3) Measure the voltage between ECM connector and chassis ground.

Connector & terminal

(B135) No. 7 (+) — Chassis ground (−):

QUESTION

Is the voltage less than 1 V?

Yes No

Replace the ECM.

Repair the short to power supply in the harness between ECM and rear oxygen sensor connector. After repair, replace the ECM.