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

Fig. 83 Water Temperature Sensor:

PURPOSE
The Engine Temperature Sensor monitors engine temperature via changes in coolant temperature.

LOCATION
In the coolant passage beneath the upper radiator hose.

OPERATION
The Engine Temperature Sensor is a negative temperature co-efficient thermistor. The greater the temperature the lower the resistance. The sensor is exposed to coolant and heat from the coolant will cause the sensor to change resistance. If the ECM reads no voltage change in the sensor circuit (from a short or open) it will store a trouble code for the sensor.