Coolant Temperature Sensor/Switch (For Computer): Description and Operation

PURPOSE
Information concerning engine operating temperature is supplied to the Digital Motor Electronic (DME) control units by the coolant temperature sensor.

OPERATION
The sensor is a Negative Temperature Co-efficient (NTC) type, in which the resistance value of the sensor decreases as the temperature of the coolant increases. The resistance value produced by the sensor is used by the DME control unit to correct fuel injector opening time during cold starting and warm-up periods. If the sensor becomes defective (open circuit), the engine will run very rich until the DME control unit has time to implement a substitute value and emergency run program.

Engine Coolant Sensor:

Coolant Temp Sensor Location: