See also:

Cleaning the wiper blades
WARNING   Before cleaning the windshield or wiper blades, switch off the windshield wipers and remove the SmartKey from the ignition lock. On vehicles with KEYLESS-GO, press the Start/S ...

General information
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 ...

Safety
The 2012 M-Class was deemed a Top Safety Pick by the Insurance Institute for Highway Safety, meaning it received the top score of Good in front- and side-impact crash tests, as well as for roof st ...