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:

    Opening and closing windows with the mechanical key
    The driver’s door key operation also allows you to open and close all door windows. To open the windows, turn the driver’s door key cylinder to the rear of the vehicle for longer than 1 se ...

    Driving with a Trailer
    WARNING When towing a trailer, exhaust gases may collect at the rear of the vehicle and enter if the liftgate, trunk/hatch, or rear-most window is open. Engine exhaust contains Carbon Monoxide ...

    Tire Messages
    SERVICE TIRE MONITOR SYSTEM On vehicles with the Tire Pressure Monitor System (TPMS), this message displays if a part on the TPMS is not working properly. The tire pressure light also flashes and t ...