DTC P0502: Vehicle Speed Sensor Low Output: Description

The Vehicle Speed Sensor (VSS) system is a pulse generator consisting of a speed sensor assembly, located in the case extension, and a toothed vehicle speed sensor reluctor wheel, which is pressed onto the final drive carrier assembly. As the vehicle drives forward, the vehicle speed sensor reluctor wheel rotates. This rotation produces a variable AC signal in the pick-up coil that is proportional to vehicle speed. The PCM uses this signal to calculate vehicle speed, shift timing and gear ratios. If the PCM detects a low vehicle speed with a high engine speed while in a drive range, then DTC P0502 sets.