Milan FWD L4-2.3L (2008)
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
ENGINE COOLANT TEMPERATURE (ECT) SENSOR
Typical Thread Type 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 the resistance increases as the temperature decreases. The varying resistance changes the voltage drop across the sensor
terminals and provides electrical signals to the PCM corresponding to temperature.
Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so that varying the resistance of the
passive sensor causes a variation in total current flow. Voltage that is dropped across a fixed resistor in a series with the sensor resistor determines the
voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.
The ECT measures the temperature of the engine coolant. The PCM uses the ECT input for fuel control and for cooling fan control. There are 3 types of
ECT sensors, threaded, push-in, and twist-lock. The ECT sensor is located in an engine coolant passage.
