Engine Coolant Temperature Sensor

The engine coolant temperature sensor is located on the engine coolant pipe. 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: Resistance Versus Temperature Graph (Engine Coolant Temperature Sensor)

Courtesy of SUBARU OF AMERICA, INC.