Vehicle Speed Sensor

VEHICLE SPEED SENSOR (VSS) BUFFER ASSEMBLY
The vehicle speed sensor (VSS) buffer assembly receives a signal from the VSS (permanent magnet generator). The signal indicates the speed of the vehicle. The VSS buffer assembly processes this signal and supplies the signal to the following:
^ The powertrain control module (PCM)
^ The cruise control module assembly
^ The speedometer assembly

VEHICLE SPEED SENSOR (VSS)
The vehicle speed sensor is mounted on the transmission assembly. The VSS produces an AC signal. The frequency of the signal is proportional to the rotation speed of the transmission assembly output shaft. The rotation speed is proportional to the speed of the vehicle.

The VSS buffer amplifies and converts the AC signal which the VSS produces. The VSS buffer assembly supplies the signal to the following components:
^ The PCM
^ The cruise control module
^ The speedometer

The VSS buffer opens and closes internal solid state switches to ground in order to produce the signal. The signal reaches the cruise control module and the speedometer assembly at a rate of 4000 pulses per mile.

The PCM converts the signal to 4000 pulses per mile. The control module and speedometer assembly internally convert the number of pulses per mile to pulses per second to determine vehicle speed.