ECT

RANGE -40°C TO 151°C, -40°F TO 304°F:
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 the internal resistance as the 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.