SBC H in the Mercedes E-Class (W211) is the start assistant, if it is active, the car does not roll back. To activate a function, you must press the brake pedal briefly when the machine is stationary. The function will notify you of the SBC H message on the computer display. If the vehicle is equipped with an automatic gearbox, when you activate SBC H, it becomes impossible to move in the position of the selector D.
