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

Engine Coolant Temperature Sensor:

1. With the key off, disconnect wire harness connector from coolant temperature sensor.

Engine Coolant Temperature Sensor:

2. Connect a high input impedance (digital) voltohmmeter to terminals A and B. The ohmmeter should read as follows:
a. ECT STET at normal operating temperature around 200°F should read approximately 700 to 1,000 ohms.
b. ECT STET at room temperature around 70°F ohmmeter should read approximately 7,000 to 13,000 ohms.
3. Test the resistance of the wire harness between the PCM connector terminal 26 and the sensor harness connector. Also check for continuity between PCM connector terminal 43 and the sensor harness connector. If the resistance is greater than 1 ohm, repair the wire harness as necessary.