Vehicle Speed Sensor

The Vehicle Speed Sensor (VSS) is a Permanent Magnet (PM) generator mounted in transmission or transfer case. The VSS sends a pulsing signal to the PCM or Digital Ratio Adapter Controller (DRAC), which passes the signal on to the PCM. The PCM then converts this signal into miles per hour by monitoring the time interval between pulses. PCM uses this sensor input in controlling Torque Converter Clutch (TCC) engagement, shift speed, etc.