Principles of Operation

Special Tools:

The Variable Assist Power Steering III (VAPSIII) system uses the Vehicle Dynamics Module (VDM) to improve steering characteristics. The level of power steering assist is based on vehicle speed. Greater power steering assist is provided at lower speeds to decrease steering effort and increase maneuverability. Less power steering assistance is provided at higher speeds to raise steering effort and increase directional stability and "road feel." Steering effort increases with vehicle speed in a smooth and continuous manner to mid-range speeds, reaching a constant level at high rates of speed.