See also:

Locking the vehicle (mechanical key)
If the vehicle can no longer be locked with the SmartKey, use the mechanical key. •► Open the driver's door.•► Close the front-passenger door, the rear doors and the trunk lid/tailgat ...

Overview
The on-board computer is activated as soon as you turn the SmartKey to position 1 in the ignition lock. You can control the multifunction display and the settings in the on-board computer using ...

4MATIC (permanent four-wheel drive)
4MATIC ensures that all four wheels are permanently driven. Together with ESP® and ETS, it improves the traction of your vehicle whenever a drive wheel spins due to insufficient grip. WARNIN ...