Coolant Temperature Sensor

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