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

Engine Coolant Temperature Sensor:

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

OPERATION
The sensor modifies a voltage signal from the Engine Control Module (ECM). The modified signal returns to the ECM as the ECT input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.