See also:

General notes
If you cannot lock or unlock the vehicle with the SmartKey, either the battery in the SmartKey is discharged, the SmartKey is faulty or the starter battery is discharged. - Check the battery in ...

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 ...

Operating the on-board computer
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 ...