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

PURPOSE
The Engine Coolant Temperature (ECT) sensor measures varying engine coolant operating temperatures.

OPERATION
The ECT sensor changes resistance in response to the engine coolant temperature. Resistance decreases as the surrounding temperature increases providing a signal to the Powertrain Control Module (PCM) that indicates the engine coolant temperature.

NOTE: In some applications of the 4.6L engine, the Cylinder Head Temperature (CHT) sensor provides the signal used by the Powertrain Control Module (PCM) in place of the ECT for functions such as, but not limited to, activating the electric cooling fans.