The Variable Effort Steering (VES) Diagnostic System Check is an organized approach to identify problems associated with the Magnetic Steering Variable Assist (MSVA) system also known as MAGNASTEER®. The MSVA 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. MSVA accomplishes this by adding or subtracting torque in the rotary input shaft to the power rack and pinion. When the vehicle is stationary, MSVA adds torque to assist the driver in turning the steering wheel. As the vehicle speed increases, the torque provided by MSVA decreases. MSVA increases resistance to the turning of the steering wheel for improved road feel at higher speeds.

A Diagnostic Trouble Code (DTC) is stored in the EBTCM for the MSVA if a malfunction occurs. No warning lamp will come ON during the malfunction. When a malfunction occurs, the DTC can be retrieved using a scan tool. A difference in power steering effort may be felt if a MSVA DTC exists.