ECT Sensor

RANGE 0-5 VOLTS:
The Engine Coolant Temperature (ECT) sensor sends a signal to the PCM relative to the engine coolant temperature. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold and the internal resistance is high, the PCM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms and the internal resistance decreases, the voltage signal will decrease and the PCM will interpret the lower voltage as a warm engine.