Engine Coolant Temperature (ECT) Sensor

ECT sensor is installed in the coolant inlet housing or intake manifold coolant passage. Sensor senses changes in temperature by monitoring the resistance of a thermistor. As temperature increases, thermistor resistance decreases.

Sensor sends temperature information to ECM for air/fuel mixture, timing and idle speed control. During warm-up from cold start, ECM increases fuel enrichment to maintain engine performance. As engine temperature increases, the ECM gradually decreases fuel enrichment until engine reaches normal operating temperature.