Description And Operation: Description
Engine Coolant Temperature Sensor (ACTS) is located in the engine coolant passage of the cylinder head for detecting the engine coolant temperature. The ACTS uses a thermistor that changes resistance with the temperature.
The electrical resistance of the ACTS decreases as the temperature increases, and increases as the temperature decreases. The reference +5V is supplied to the ACTS via a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the ACTS are connected in series. When the resistance value of the thermistor in the ACTS changes according to the engine coolant temperature, the output voltage also changes.
During cold engine operation, the ECM increases the fuel injection duration and controls the ignition timing using the information of engine coolant temperature to avoid engine stalling and improve driveability.