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

Engine Coolant Temperature (ECT) sensor:

PURPOSE
By measuring the amount of resistance at the sensor, the Engine Control Module (ECM) can adjust the length of injector opening time required by the engine.

OPERATION
As water temperature increases, sensor resistance decreases. The ECM receives sensor information as resistance to ground. Water temperature information is used to determine proper fuel delivery.

CONSTRUCTION
Temperature sensitive resistor (thermistor).