Engine Coolant Temperature (ECT) Sensor
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
The ECT sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases, and 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.
The ECT sensor is located on the upper coolant inlet housing. The ECT sensor measures the temperature of the engine coolant and provides a feedback signal to the PCM. The PCM uses the ECT sensor input fuel and cooling fan control.