See also:

SmartKey
Display messages Possible causes/consequences and Solutions Key Does Not Belong to Vehicle You have put the wrong SmartKey in the ignition lock. Use the correct Smart ...

Styling
The 2012 M-Class retains many of the previous generation's styling cues, like a wide front grille and forward-swept C-pillars, but the new design looks more substantial and imposing. Contributing ...

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 ...