Circuit/System Description
WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The power steering control module (PSCM) receives a vehicle speed message from the engine control module (ECM) via the serial data circuit. The PSCM uses this vehicle speed message, and other inputs, to determine the desired amount of steering assist. At lower speeds, more assist is provided for easy turning during parking maneuvers. At higher speeds, less assist is provided for improved road feel and directional stability.