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

Water Temperature Sensor (THW):

The Coolant Temperature Sensor, located on the top, rear of the engine, monitors coolant temperature with a thermistor whose resistance varies according to engine temperature. The ECU uses this signal to control open/closed loop operation of the fuel injection system, overdrive on electronic transaxles, spark advance (ESA), idle speed control system and EGR system. The THW inputs the ECU through terminal THW.