DeVille V8-4.9L VIN B (1995)
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
ECT Location
DESCRIPTION
The Engine Coolant Temperature (ECT) Sensor is a thermistor (a resistor which changes value based on temperature) mounted in the engine
coolant flow. At cold coolant temperatures, the ECT sensor resistance is high and at hot coolant temperatures, the resistance of the sensor is low.
The Powertrain Control Module (PCM) supplies a 5 volt reference signal and a ground to the sensor and measures the voltage signal as it is
changed by the sensor. The voltage is close to 5 volts at cold temperatures and close to zero volts at hot temperatures.
The PCM uses ECT information for fuel enrichment, ignition control, Evaporative Emission (EVAP) control, idle speed control and "Closed
Loop" fuel control. A faulty ECT sensor may cause various driveability conditions and should set a Diagnostic Trouble Code.
