3500 4x2 Pickup L6-359 5.9L DSL Turbo (1994)
Vehicle Speed Sensor: Description and Operation
Vehicle Speed Sensor
PURPOSE
The sensor input is used by the Powertrain Control Module (PCM) to determine vehicle speed and distance traveled.
OPERATION
The speed sensor generates 8 pulses per sensor revolution. These signals, in conjunction with a closed throttle signal from the throttle position
sensor (auto. trans. only), indicate a closed throttle deceleration to the PCM. When the vehicle is stopped at idle, a closed throttle signal is
received by the PCM (but a speed sensor signal is not received).
In addition to determining distance and vehicle speed, the output from the sensor is used to help control:
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Speed control operation
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Transmission overdrive operation
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Transmission torque converter electrical operation
