Circuit/System Description
WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The output shaft speed (OSS) sensor is a pulse generator consisting of a speed sensor assembly, located in the case extension, and a toothed reluctor wheel, which is pressed onto the final drive carrier assembly. As the vehicle drives forward, the reluctor wheel rotates. This rotation produces a variable AC signal in the pick-up coil of the output shaft sensor that is proportional to vehicle speed. The transmission control module (TCM) uses this signal in order to calculate vehicle speed, shift timing, and gear ratios.