Engine Coolant Temperature Sensor

Engine Coolant Temperature (ECT) sensor is installed in coolant inlet housing or intake manifold coolant passage. ECT sensor detects changes in temperature by monitoring resistance of a thermistor. As temperature increases, thermistor resistance decreases.

ECT 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, ECM gradually decreases fuel enrichment until engine reaches normal operating temperature.