DTC P0500: Vehicle Speed Sensor ("S" & "T" Series With M/T Only): Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Sonoma, 2003 GMC Safari, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.
The Vehicle Speed Sensor (VSS) assembly provides vehicle speed information to the Powertrain Control Module (PCM). The VSS assembly is a permanent magnet generator. The VSS produces alternating current (AC) as the rotor teeth on the output shaft of the transmission (2WD) or transfer case (4WD) pass through the sensor's magnetic field. The frequency and amplitude of the AC waveform both increase as vehicle speed increases. If the PCM detects no vehicle speed for a specified length of time while other sensors indicate that the vehicle is moving, DTC P0500 sets.