The Variable Effort Steering (VES) system or MAGNASTEER® varies the amount of effort required to steer the vehicle as vehicle speed changes. At low speeds, the system provides minimal steering effort for easy turning and parking maneuvers. Steering effort is increased at higher speeds to provide firmer steering (road feel) and directional stability. VES works in parallel with the base torsion bar in the power steering system.
The VES control module communicates on the high speed bus and uses vehicle speed and the steering wheel angle speed to command a current that is most appropriate for each speed to the VES actuator in the steering rack and pinion. The actuator is a variable electromagnetic actuator, which consists of one multiple-pole ring-style permanent magnet, with a pole piece, and an electromagnetic coil assembly on each side. By commanding currents between -3 to +3 Amps through the coils the steering effort will be adapted to the vehicle’s speed.
At lowest speed, around 5 km/h (3 mph) the coils are polarized in such a way that the magnetic forces are repelling each others and hardly any effort is required to turn the ring magnet between them.
At mid speed, around 70 km/h (45 mph), no current is sent through the coils and steering is assisted by hydraulics only. At high speeds the coils are polarized in such a way that the magnetic forces are attracting each others and high effort is required to turn the ring magnet between them.
The VES control module communicates on the HS GMLAN bus.
The VES control module has the ability to detect malfunctions in the actuator. Any malfunctions detected will cause the system to ramp to zero amps. Steering will be assisted by hydraulics only and a DTC is set.
Special Tools and Equipment

Power Steering System Description and Operation
Steering Wheel and ColumnBluetooth (Infotainment Controls)
For information about how to navigate the menu system using the infotainment
controls.
Pairing
A Bluetooth-enabled cell phone must be paired to the Bluetooth system and then
connected to the vehicle before it can be used. See your cell phone manufacturer's
user guide for Bluetooth functi ...
Rear Seats
Either side of the rear seatback can be folded.
To fold the rear seatbacks:
1. Place the front seatbacks in the upright position.
Notice: Folding a rear seat with the safety belts still fastened may
cause damage to the seat or the safety belts. Always unbuckle the safety belts and
return them ...
Inflatable Restraint Seat Position Sensors - If Equipped
The inflatable restraint seat position sensor is used to determine the
proximity of a front driver or passenger seat position with respect to
the frontal air bag. The seat position sensor interfaces with the inflatable
restraint sensing and diagnostic module (SDM). The state of the
seat positi ...