BAS (Brake Assist System)
Observe the "Important safety notes"
section.
BAS operates in emergency braking situations. If you depress the brake pedal quickly, BAS automatically boosts the braking force, thus shortening the stopping distance.
► Keep the brake pedal firmly depressed until the emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will function as usual once you release the brake pedal. BAS is deactivated.
WARNING 
If the BAS malfunctions, the brake system still
functions, but without the additional brake
boost available that the BAS would normally
provide in an emergency braking maneuver.
Therefore, the braking distance may increase.
See also:
Cleaning the steering wheel and gear or selector lever
Thoroughly wipe with a damp cloth or use leather care agents that have
been recommended and approved by Mercedes- Benz.
...
Brake fluid level
If you notice that the brake fluid level in
the brake fluid reservoir has fallen to the
MIN mark or less, check the brake system
immediately for leaks. Also check the
thickness of the brake lini ...
Center console, lower section
Stowage compartment Ashtray Cigarette lighter Power socket
Selector lever
Cup holder
Stowage compartment
Audio/COMAND controller
Selects the drive program
...