Vehicle Speed Sensor
WARNING: This page is about a different car, the 2002 Mazda Millenia and 2001 Mazda Millenia. However, it is still accessible from the selected car via links, so may be relevant.
Vehicle Speed Sensor (VSS) is a magnetic pick-up that is mounted to transaxle case and driven by gear on differential. Pulse signals are sent through speedometer (also known as speedometer sensor) in instrument cluster to PCM.
Courtesy of MAZDA MOTORS CORP.