The Vehicle Speed (VSS) Sensor input is used by the PCM to determine vehicle speed. The VSS generates a signal that increases in frequency proportionate to vehicle speed. The PCM has a base frequency stored in memory for a distance of one mile. By comparing the input and stored value, the PCM calculates vehicle speed.
VSS types include: photo-optic, permanent magnet generators(The Vehicle Speed Sensor (VSS) is a magnetic pick-up that sends a signal to the Powertrain Control Module (PCM).) or hall effect technology. The PCM may use other sensors on the vehicle (ABS Wheel Speed) to validate VSS operation.
VSS information is used to calculate vehicle loads including: torque converter application, cruise control, fuel cutoff/speed governance strategies, instrument panel speedometer and more.
Modified drivetrain components such as final gear sets and/or tires can alter VSS input values to the PCM. Improper signals can alter Torque Converter Clutch (TCC) application, shift points, cruise control operation as well as many other systems relying on vehicle speed input.
The VSS is located half-way down the right-hand side of the transmission assembly.
REMOVAL & INSTALLATION (newer models)