Vehicle Speed Sensor

WARNING: This page is about a different car, the 2008 Buick Lucerne. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: View Of Vehicle Speed Sensor

Courtesy of GENERAL MOTORS CORP.

The vehicle speed sensor (VSS) is mounted on the transmission case extension facing toward the right wheel. This sensor consists of a permanent magnet surrounded by a coil of wire. The sensor mounts into the extension and maintains a slight air gap (0.045-0.109 in) between itself and a rotor which is located on the differential. The VSS measures the speed of the rotor, which contains 31 teeth. As the differential rotates, an AC signal is induced in the VSS. The AC signal varies in frequency and voltage output:

Low speed = low Hz and voltage amplitude
High speed = high Hz and voltage amplitude

This input is used for TCC, line pressure, shift timing and torque management controls.

Sensor resistance should be 1300-1950 ohms when measured at 20-100°C (68-212°F). Output voltage varies with speed from a minimum of 0.5 volts AC at 100 RPM, to more than 100 volts AC at 8000 RPM.