Circuit/System Description
WARNING: This page is about a different car, the 2009 Saturn Vue. 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, along with the torque sensor and motor position sensor 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.