How to test a faulty engine coolant temperature sensor ECT fault codes P0118 P0115 P0116 P0117 P0119

How to test an engine coolant temperature sensor with a voltmeter and what readings should you get? What does fault code P0118 mean? How to fix fault code P0115? How to check the resistance of a sensor. What is a NTC sensor? How to check the voltage of a sensor? The Engine Coolant Temperature ECT sensor is a variable resistor or thermistor. It’s an NTC Negative Temperature Coefficient thermistor where, as the temperature increases, it’s resistance decreases. An ECT sensor is connected to the main computer (powertrain control module PCM or Engine control module ECM or Engine Control Unit ECU). The PCM supplies a reference voltage (typically 5 Volt) and constantly monitors the ECT sensor signal. Based on this signal, the PCM adjusts the engine performance and operates the electric radiator fans when the temperature reaches a pre-determined level. If the signal from the sensor is missing, or it is outside of the expected range, the PCM turns on the Check Engine light and stores the related t