Engine Control System

DIAGNOSIS:
- The engine coolant temperature sensor signal is abnormal.
- The harness connector between ECM and engine coolant temperature sensor is in short or open.

TROUBLE SYMPTOM:
- Hard to start
- Erroneous idling
- Poor driving performance




1. CHECK ENGINE COOLANT TEMPERATURE SENSOR.
1. Turn ignition switch to OFF.
2. Disconnect connector from engine coolant temperature sensor.
3. Measure resistance between engine coolant temperature sensor terminals.

Terminals / Specified resistance:
No.1 - No.2 / 2.0 - 3.0 kOhm at 20 °C (68 °F)
No.1 - No.2 / 270 - 370 kOhm at 80 °C (178 °F)

2. CHECK HARNESS CONNECTOR BETWEEN ECM AND ENGINE COOLANT TEMPERATURE SENSOR.




1. Disconnect connector from ECM.
2. Measure resistance of harness connector between ECM and engine coolant temperature connector.

Connector & terminal / Specified resistance:
(E30) No.3 - (E4) No.1 / 10 Ohm, max.
(E30) No.11 - (E4) No.2 / 10 Ohm, max.




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

Connector & terminal / Specified resistance:
(E4) No.1 - Body / 1 MOhm, min.
(E4) No.2 - Body / 1 MOhm, min.