3500 4x4 Pickup V10-488 8.0L Magnum (1994)
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
PURPOSE
The sensor element extends into the coolant passage where it maintains constant contact with the engine coolant. The Powertrain Control Module
(PCM) uses this sensor to measure the temperature of engine coolant.
OPERATION
The PCM sends out a reference voltage of approximately five (5) volts to the engine coolant temperature sensor. As coolant temperature changes,
the internal resistance of the sensor will change, causing a varying voltage drop across the sensor. The PCM reads the voltage drop across the
sensor as engine coolant temperature.
Based on the amount of voltage drop at the coolant sensor, the PCM will, adjust the fuel injector pulse width (a cold engine will receive a longer
pulse width, allowing for a richer mixture), compensate for condensation of fuel in the intake manifold, monitor and adjust engine warm-up speed,
and advance ignition timing when the engine is cold.