Mercedes-Benz GL-Class: Braking - ABS (Anti-lock Braking System) - Driving safety systems - Safety - Mercedes-Benz GL-Class Owner's ManualMercedes-Benz GL-Class: Braking

If ABS intervenes when braking, you will feel a pulsing in the brake pedal.

If ABS intervenes: continue to depress the brake pedal with force until the braking situation is over.
To make a full brake application:

depress the brake pedal with full force.

The pulsating brake pedal can be an indication of hazardous road conditions, and functions as a reminder to take extra care while driving.

WARNING Do not pump the brake pedal. Use firm, steady 
Do not pump the brake pedal. Use firm, steady brake pedal pressure instead. Pumping the brake pedal defeats the purpose of the ABS and significantly reduces braking effectiveness.

    Important safety notes
    Observe the "Important safety notes" section. ABS regulates brake pressure in such a way that the wheels do not lock when you brake. This allows you to continue steering the vehicl ...

    Off-road ABS
    An ABS mode specifically suited to off-road terrain is activated automatically if the offroad drive program is activated or the LOW RANGE off-road gear is selected. At speeds below 18 mph(30 km ...

    See also:

    Tow/Haul Mode
    (Tow/Haul): The vehicle may have a Tow/Haul mode. The button is located on the instrument panel under the climate controls. Push the button to activate the system. Push it again to deactivate the ...

    Airbag Readiness Light
    The system checks the airbag's electrical system for possible malfunctions. If the light stays on it indicates there is an electrical problem. The system check includes the airbag sensor(s), pas ...

    Ultrasonic Parking Assist
    If available, the Ultrasonic Rear Parking Assist (URPA) system assists the driver with parking and avoiding objects while in R (Reverse). URPA operates at speeds less than 8 km/h (5 mph). The sen ...