GM Service Manual Online
For 1990-2009 cars only

The Magnetic Steering Variable Assist (MAGNASTEER®) system varies the driver effort required to steer as the vehicle speed changes. At low speeds, the system requires minimum steering effort for easy turning and parking maneuvers. Steering effort is increased at higher speeds in order to provide the driver with firmer steering (road feel) and directional stability. MAGNASTEER® accomplishes this by adding or subtracting torque in the rotary input shaft to the power rack and pinion. When the vehicle is stationary, MAGNASTEER® adds torque to assist the driver in turning the steering wheel. As the vehicle speed increases, the torque provided by MAGNASTEER® decreases. MAGNASTEER® increases resistance to the turning of the steering wheel for improved road feel at higher speeds.