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

Fig. 4 Engine coolant temperature sensor:

The ECT, Fig. 8, sensor detects the temperature of engine coolant and supplies information to the ECA assembly. The ECT sensor is threaded into the heater outlet fitting on the engine. For engine control applications, the ECT signal is used to modify ignition timing, EGR flow and air/fuel mixture. On models with an electronic instrument cluster, the ECT output is used to control the coolant temperature indicator.