Abs Repair Instructions: Notes
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 inside the ABS Control Module -J104- 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 indicator lamp is lit up, the rear wheels may lock prematurely during braking!
Left-Hand Drive Configuration
1 - ABS Hydraulic Unit -N55- and ABS Control Module -J104-
2 - Brake Booster
The ABS Hydraulic Unit -N55- and ABS Control Module -J104- are one unit. Separation can only be performed when removed from vehicle. The hydraulic pump may also not be separated from the ABS Hydraulic Unit -N55-.