General Information

General Information

The ABS brake system is divided diagonally (two circuits). The vacuum brake servo unit boosts the brakes pneumatically.

Models with ABS do not have a mechanical brake pressure regulator. A specially coordinated software program in the control module determines brake pressure allocation at the rear axle.

• ABS malfunctions do not affect the brake system and the booster. Conventional brake system stays operative even without ABS. A change in braking behavior should be checked. When the ABS warning lamp is lit up, the rear wheels may lock prematurely during braking!

ABS Allocation






1 Hydraulic unit and control module
2 Brake booster

Control module - 1 - and hydraulic unit - 2 - comprise a single unit. Separation can only be performed when removed from vehicle. The hydraulic pump - 3 - must not be separated from the hydraulic unit.






Separation is not possible on vehicles with ABS/EDL/ASR/ESP with hydraulic brake booster or hill assist.