Fuel filler flap
The fuel filler flap is unlocked or locked automatically when you open or close the vehicle with the SmartKey or using KEYLESSGO.
The position of the fuel filler cap is displayed
in the instrument cluster 
. The
arrow
next to the filling pump indicates the side of
the vehicle.
Example: Sedan
1. To open the fuel filler flap
2. To insert the fuel filler cap
3. Tire pressure table
4. Fuel type
See also:
Vehicle data, GL 550
The data stated here refers specifically to a
vehicle with standard equipment. Consult an
authorized Mercedes-Benz Center for the
data for all vehicle variants and trim levels.
...
General notes
WARNING
If the vehicle becomes trapped in snow, ensure that snow is kept away from the
exhaust pipe and from around the vehicle as long as the engine is running. Otherwise,
poisonous carbon ...
Problems with the side windows
Problem: a side window cannot be closed
because it is blocked by objects, e.g.
leaves in the window guide.
Remove the objects.
Close the side window.
Problem: a side window cannot be closed
...