Engine Coolant Temperature Sensor

The engine coolant temperature sensor is located in the engine coolant passage. The sensor uses a thermistor whose resistance changes inversely with temperature. Resistance signals as engine coolant temperature information are transmitted to the ECM to make fuel injection, ignition timing, purge control solenoid valve and other controls.

Fig 1: Cut View Of Engine Coolant Temperature Sensor And Temperature Resistance Graph

Courtesy of SUBARU OF AMERICA, INC.