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

PURPOSE/OPERATION

The engine coolant temperature (ECT) sensor is installed in the engine coolant passage of the cylinder head, detects engine coolant temperature and emits signals to the engine control module (ECM). This part employs a thermistor which is sensitive to changes in temperature. The electric resistance of a thermistor decreases in response to temperature rise. The ECM judges engine coolant temperature by the sensor output voltage and provides optimum fuel enrichment when the engine is cold.