Coolant Temperature Sensor/Switch (For Computer): Description and Operation

PURPOSE
The Engine Coolant Temperature (ECT) Sensor is used to detect engine coolant temperature.

OPERATION
The Engine Coolant Temperature Sensor modifies a voltage signal from the Engine Control Module (ECM). This modified signal returns to the ECM as the ECT input signal. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases. If the ECM reads no voltage change in the sensor circuit (from a short or open) it will store a trouble code for the sensor.