Engine Coolant Temperature (ECT) Sensor

ECT sensor is a thermistor installed in the coolant inlet housing or intake manifold coolant passage. As temperature increases, thermistor resistance decreases and the PCM gradually decreases fuel enrichment until engine reaches normal operating temperature. Sensor changes return voltage signal to PCM depending upon resistance of a thermistor. PCM uses this information for varying air/fuel mixture, timing and idle speed control. During warm-up from cold start, PCM increases fuel enrichment to maintain engine performance.