Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Antilock Brake System
The Antilock Brake System (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 indicator lamp is on, the rear wheels may lock prematurely during braking!
1 - Hydraulic unit and control module
2 - Brake booster
The control module and hydraulic unit form one component. Separation is not possible. The hydraulic pump must also not be separated from the hydraulic unit.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.