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

MAT & CTS Sensor Characteristics:

Located at the side of intake manifold, this sensor measures the temperature of the engine coolant and converts its change into a resistance through the thermistor similar to the Manifold Air Temperature (MAT) sensor. That is, as coolant temperature lowers, resistance increases and as it rises, resistance decreases. By monitoring the resistance of the CTS, the ECM detects the engine coolant temperature.