See also:

Problems with the SmartKey
Problem Possible causes/consequences and Solutions You cannot lock or unlock the vehicle using the SmartKey. The SmartKey battery is discharged or nearly discharged. ...

Adjusting the head restraint height electrically
To adjust the head restraint height: slide the switch for head restraint adjustment up or down in the direction of the arrow. ...

Performance
The nice thing about being able to afford the ML550 is the 382-horsepower V-8 under its hood. Calling this SUV "fast" is an understatement. Mercedes says it goes from zero to 60 mph in 5 ...