Cylinder Head Temperature (CHT) Sensor
WARNING: This page is about a different car, the 2009 Mercury Grand Marquis and 2009 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
The cylinder head temperature (CHT) sensor is a thermistor device in which resistance changes with the temperature. The electrical resistance of a thermistor decreases as temperature increases, and the resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature.