Vehicle Speed Sensor
WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
The Vehicle Speed Sensor (VSS) is mounted on the transaxle. As the transaxle turns the VSS, the VSS provides the speedometer with a vehicle speed input through voltage pulses. Each revolution of the axle shaft equals 4 pulses. This input is used to drive the speedometer. The speedometer converts the vehicle speed input to a more precise output which is sent to the Powertrain Control Module (PCM) and the cruise control module, if equipped. The PCM sends a 5-volt carrier signal to the speedometers vehicle speed output control circuit. On this same circuit, the speedometer produces a pulse width modulated signal that the PCM, and the cruise control module, use to determine the vehicle speed.