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

ENGINE COOLANT TEMPERATURE (ECT) SENSOR - ECM INPUT

Fig. 10 Engine Coolant Temperature Sensor:

The Engine Coolant Temperature (ECT) sensor is installed into the front of the cylinder head near to the thermostat housing and protrudes into a water jacket.

The ECT sensor provides an input voltage to the Engine Control Module (ECM) to monitor coolant temperature. The ECM uses this input along with inputs from other sensors for engine protection, fuel timing and fuel control. As coolant temperature varies, the coolant temperature sensor resistance will change. This change in resistance results in a different input voltage to the ECM.