Grand Prix V6-204 3.4L DOHC VIN X SFI (1995)
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Vehicle Speed Sensor: Description and Operation
Circuit Operation
The Vehicle Speed Sensor (VSS) is a gear-driven Permanent Magnet Generator housed in the vehicle's Transaxle. This sensor generates a sine wave
output with a frequency proportional to vehicle speed. The Powertrain Control Module (PCM) converts this signal to an output that is switched to
ground at a frequency of 4000 pulses per mile at the CKT 389 output. This output is pulled up to 5 volts or greater by the components that use this
speed signal as an input.