Engine Coolant Temperature (ECT) Sensor
WARNING: This page is about a different car, the 2002 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.
The engine coolant temperature (ECT) sensor detects temperature of engine coolant and supplies the information to the powertrain control module. The ECT sensor is used to control torque converter clutch (TCC) operation. The ECT is installed in the heater outlet fitting or cooling passage on the engine. For engine control applications, the ECT signal is used to modify ignition timing, EGR flow and air-to-fuel ratio as a function of engine coolant temperature.