Engine Control System

DIAGNOSIS:
- The oxygen sensor is not in function.
- The harness connector between ECM and oxygen sensor is in short or open.

TROUBLE SYMPTOM:
- Failure of engine to start
- Erroneous idling
- Poor driving performance
- Engine stalls.
- Idle mixture is out of specifications.

1. CHECK HARNESS CONNECTOR BETWEEN ECM AND OXYGEN SENSOR.




1. Disconnect connectors from ECM and oxygen sensor.
2. Measure resistance of harness connector between ECM and oxygen sensor.

Connector & terminal / Specified resistance:
(E30) No. 10 - (E23) No.4 / 0 Ohm




3. Measure resistance of harness connector between oxygen sensor and body to make sure that circuit does not short.

Connector & terminal / Specified resistance:
(E23) No.4 - Body / 1 MOhm, min.




2. CHECK OXYGEN SENSOR.
1. Idle engine.
2. Disconnect oxygen sensor connector.
3. Measure voltage between oxygen sensor terminal and body.

Connector & terminal / Specified voltage:
No.4 - Body / 0.1 - 1.0 V