The engine coolant temperature (ECT) sensor is a thermistor that is a resistor that changes its resistance value based on temperature changes. This change in resistance directly affects the voltage signal from the sensor to the PCM. The sensor's resistance values increase when the temperature decreases, but they decrease as the sensor temperature increases. Any problem in the ECT sensor circuit will set a diagnostic trouble code (DTC). To replace this sensor, make sure that you turn off the ignition key and drain about one gallon from the cooling system. The electrical connector should be disconnected before carefully unscrewing the sensor. Wrap Teflon sealing tape around the new sensor's threads so as to avoid leakage and thread corrosion. Installation is simply opposite of removal. Nevertheless, pay attention to how you handle coolant sensors because if damaged, it will affect normal operation of entire fuel injection system. Finally, add coolant as required.