Vehicle Speed Sensor
WARNING: This page is about a different car, the 2002 Subaru Outback and 2002 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.
The vehicle speed sensor (VSS) mainly consists of a Hall IC, magnet ring, driven shaft, and spring. See Fig 1 . The VSS uses the Hall IC pick-up to generate speed signals (M/T model). The sensor is installed on the transmission case and detects the transmission output gear's rotating speed. The VSS generates four pulses per rotation of the speed sensor driven shaft and sends the signal to the speedometer. As the driven key rotates, the magnet turns, which causes the Hall IC's magnetic field to change. The Hall IC generates a signal that corresponds to the change in the magnetic field. One turn of the driven key in the speed sensor sends four pulses to the combination meter, engine control module, and cruise control module. See Fig 2 .