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

Engine Coolant Temperature Sensor:

The engine Coolant Temperature Sensor (CTS) is a thermistor that is located in the engine coolant flow. When the coolant temperature is low, the sensor produces a high resistance. When the coolant temperature is high, the sensor produces a low resistance. Each resistance value correlates to a specific engine coolant temperature. The PCM measures the resistance and calculates the engine temperature.