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

A thermistor built into the engine coolant temperature sensor changes the resistance value according to the engine coolant temperature.The lower the coolant temperature, the greater the thermistor resistance value and the higher the coolant temperature, the lower the thermistor resistance value. Based on this signal, the ECM increases the fuel injection volume to improve driveability during cold engine operation.
If the ECM detects the DTC P0115, it operates the fail safe function in which the engine coolant temp. is assumed to be 80°C (176°F).