Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION

NOTE: Perform the following inspection only when directed.

Resistance Inspection

1. Remove the ECT sensor.
2. Place the ECT sensor in water with a thermometer, and heat the water gradually.







3. Measure the resistance between ECT sensor terminals A and B using an ohmmeter.
- If the ECT sensor is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection".
- If not as specified, replace the ECT sensor.




ECT sensor characteristics graph (reference)

Circuit Open/Short Inspection




1. Disconnect the PCM connector.
2. Inspect the following harnesses for open or short circuit. (Continuity check)

Open circuit
- ECT sensor terminal A and PCM terminal 41
- ECT sensor terminal B and PCM terminal 20

Short circuit
- ECT sensor terminal A and power supply
- ECT sensor terminal A and body GND
- ECT sensor terminal B and power supply