Vehicle Speed Sensor
WARNING: This page is about a different car, the 2003 GMC Savana and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
The Vehicle Speed Sensor (VSS) is a Permanent Magnet (PM) generator mounted in transmission. See Fig 1 . The VSS sends a pulsing signal to the PCM. The PCM then converts this signal into miles per hour by monitoring the time interval between pulses. PCM uses this sensor input in controlling Torque Converter Clutch (TCC) engagement, shift speed, etc.