Lumina V6-191 3.1L VIN T MFI (1993)
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
Engine Coolant Temperature Sensor
PURPOSE
The Engine Coolant Temperature (ECT) Sensor is used to control:
^
Fuel delivery
^
Torque Converter Clutch (TCC)
^
Engine Spark Timing (EST)
^
Controlled Canister Purge (CCP)
^
Idle Air Control (IAC)
^
Cooling Fan
OPERATION:
The ECT is a thermistor that is located in the engine coolant flow. When the coolant temperature is low, the sensor produces a high resistance.
When the coolant temperature is high, the sensor produces a low resistance.
The ECM sends a 5.0 volt signal to the ECT through a resistor in the computer and measures the voltage. The voltage will be high or low
depending on coolant temperature. With the ECT varying its resistance, the ECM can sense engine coolant temperature by reading the varying
voltage.
LOCATION:
Engine thermostat and coolant outlet.