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

Engine Coolant Temperature Sensor:

Engine Coolant Temperature Sensor (ECTS):

PURPOSE
The Engine Coolant Temperature Sensor (ECTS) is used to detect changes in engine coolant temperature.

OPERATION
The sensor is exposed to coolant. Heat from the coolant will cause the sensor to change resistance. The greater the temperature the lower the resistance. A 5 Volt reference signal is sent from the Engine Control Module (ECM) which passes through the ECTS and is modified by the ECTS resistance. This modified signal is the ECTS input to the ECM.

DESIGN
The Engine Coolant Temperature Sensor is a negative temperature co-efficient thermistor.

NOTE: If the ECM reads no voltage change in the sensor circuit (from a short or open) it will store the Diagnostic Trouble Code (DTC) No.13 for the sensor.