Engine Coolant Temperature (ECT) Sensor
WARNING: This page is about a different car, the 2012 Ford F550 Super Duty and 2012 Ford F450 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The ECT sensor is a 2-wire thermistor which changes resistance as temperature changes. The resistance of the sensor increases as engine temperature decreases and the voltage measured by the PCM increases. The PCM uses this information to determine TCC operation.