ECT

The scan tool displays a range of -39°C to 140°C (-38°F to 284°F). The Engine Coolant Temperature (ECT) sensor is mounted in the cylinder head of the left bank. The PCM applies 5.0 Volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the PCM monitors a high signal voltage and interprets the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases and the PCM interprets the lower voltage as a warm engine.