Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The vehicle speed sensor (VSS), also called the output shaft speed sensor (OSS) creates an AC voltage as the rotor teeth pass through the magnetic field of the sensor. The transmission control module (TCM) converts the AC voltage into a vehicle speed signal, which is used to determine shift timing and torque converter clutch (TCC) scheduling. The TCM also provides a replicated transmission output speed signal (RTOSS) to the engine control module (ECM).