Circuit/System Description

The automatic transmission (AT) OSS/VSS system is a 2-wire pulse generator consisting of a speed sensor assembly, located in the case extension, and a toothed output speed sensor (OSS/VSS) reluctor wheel, which is pressed onto the final drive carrier assembly. As the vehicle drives forward, the OSS/VSS reluctor wheel rotates. This rotation produces a variable AC signal in the pick-up coil that is proportional to vehicle speed. The transmission control module (TCM) uses this signal in order to calculate vehicle speed, shift timing, torque converter clutch (TCC) slip speed, and gear ratios.