DTC P0117-00: Engine Coolant Temperature Circuit Low Input: General Description

The Engine Coolant Temperature Sensor (ECTS) is located in the engine coolant passage of the cylinder head to detect engine coolant temperature. The ECTS uses a thermistor whose resistance changes with the temperature. The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. The reference 5V from the ECM is supplied to the ECTS via a resistor in the ECM. When the resistance value of the thermistor in the ECTS 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 ECTS signal to avoid engine stalling and to improve drivability.