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

Fig. 34 Coolant Temperature (TW) Sensor And Characteristics Chart:

The coolant temperature (TW) sensor, located in the thermostat housing, is a temperature sensitive resistor (thermistor). The resistance of the thermistor decreases as the coolant temperature increases. Engine temperature is used by the ECU to determine ignition timing, fuel injector duration, purge control, idle speed, and EGR activation.