G 2500 3/4 Ton Van V8-6.5L DSL Turbo VIN F (1996)
Vehicle Speed Sensor Signal Buffer: Description and Operation
Circuit Operation
The Vehicle Speed Sensor (VSS) is a gear-driven permanent magnet generator housed in the vehicle's transmission. The sensor produces a sine-wave
output with a frequency proportional to vehicle speed. Twisted pair PPL/WHT (821) and LT GRY/BLK (822) wires deliver this signal to the Vehicle
Speed Sensor Buffer. The Vehicle Speed Sensor Buffer converts this signal to an output signal which is switched to ground at a frequency of 4000
pulses per mile. This output is ported to the DK GRN/WHT (817) wire, to the DK GRN (389) wire, and to the WHT (696) wire. The Radio output is
used to produce speed compensated volume (Refer to Radio/Stereo). See: Accessories and Optional Equipment/Radio, Stereo, and Compact Disc
The Instrument Cluster output is used to generate speedometer and odometer indications (Refer to Instrument Cluster). This signal is also used by the
Powertrain Control Module. A second output at 40 pulses-per-revolution output is provided at the BRN (437) wire for use in the Powertrain Control
Module. The Powertrain Control Module uses these signals for control of Torque Converter Clutch (TCC), shift solenoids, and cruise control operations.
A final output to the Four Wheel Antilock Brake System (ABS) is ported to the WHT (696) wire for use by the ABS System.
