C 2500 Suburban 2WD V8-6.5L DSL Turbo VIN F (1995)
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
Engine Coolant Temperature (ECT) Sensor
PURPOSE
The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) mounted in the engine
coolant stream. Low coolant temperature produces a high resistance (100,000 ohms at -40° C (-40° F) while high temperature causes low
resistance (70 ohms at 130° C (266° F).
OPERATION
The PCM supplies a 5 volt signal to the Engine Coolant Temperature (ECT) sensor through a resistor in the PCM and measures the voltage. The
voltage will be high when the engine is cold, and low when the engine is hot. By measuring the voltage, the PCM knows the engine coolant
temperature. Engine coolant temperature affects fuel control and the glow plug system.
