Engine Coolant Temperature (ECT) Sensor Description and Operation

Description

The Engine Coolant Temperature Sensor (ECTS) is installed in the engine coolant passage through the cylinder head to detect the engine coolant temperature. The ECTS uses a thermistor whose electrical resistance changes with temperature. The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. A +5 V reference voltage is supplied to the ECTS through a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the ECTS are connected in series. As the resistance of the thermistor in the ECTS changes according to the engine coolant temperature, the output voltage also changes. The ECM uses the engine coolant temperature information to control the injection duration and adjust the ignition timing to prevent engine stalling and improve drivability. When the engine is cold, the ECM increases the fuel injection duration and adjusts the ignition timing using the engine coolant temperature information to prevent engine stalling and improve drivability.