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

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Engine Coolant Temperature (ECT) Sensor:

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.

A cooling system concern such as low coolant or coolant loss could cause an overheating condition. As a result, damage to major engine components could occur. Using both the ECT sensor and fail-safe cooling strategy, the PCM prevents damage by allowing air cooling of the engine and limp home capability.