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.
Control Module, Separating From Hydraulic Unit
Special tools and workshop equipment required
- ESD Work Surface: VAS6613
- TORX® Insert T25
- If the ABS Control Module -J104- is faulty, then the control module is to be separated from the ABS Hydraulic Unit -N55- and only the control module replaced.
- If the ABS Hydraulic Unit -N55- is faulty, then replace the ABS Hydraulic Unit -N55- together with the ABS Control Module -J104-.
- To separate the ABS Control Module -J104- and the ABS Hydraulic Unit -N55- the unit must be removed.
- The return flow pump may also not be separated from the ABS Hydraulic Unit -N55-.
- The circuit board is exposed when the ABS Control Module -J104- is removed.
- Protect the ABS Control Module -J104- from moisture and dirt particles from getting inside.
- Avoid build-up of static electricity!
This build-up of static electricity can lead to malfunctions when contacting electrical components.
-- Touch a grounded object, before working on electrical equipment : VAS6613 . Do not touch directly on the connector terminals or the electrical components.
-- Place the ABS Hydraulic Unit -N55- with the ABS Control Module -J104- on the : VAS6613 .
-- Remove the three TORX® bolts from the ABS Control Module -J104- and set aside immediately (risk of confusing them with the new TORX® bolts).
-- Place the ABS Hydraulic Unit -N55- with the ABS Control Module -J104- upward on the : VAS6613 .
-- Remove the ABS Control Module -J104- from the ABS Hydraulic Unit -N55- without tilting it.
-- Cover ABS Control Module -J104- solenoid coils with a lint-free cloth.
-- Clean the ABS Hydraulic Unit -N55- sealing surface using mineral spirits and a lint-free cloth.
The ABS Hydraulic Unit -N55- sealing surface must not be worked with a file, metal scraper, sand paper or similar.
If the ABS Hydraulic Unit -N55- sealing surface is damaged (for example through grooves or scrapes) the ABS Hydraulic Unit -N55- must be replaced with the ABS Control Module -J104-.
The seal on the ABS Control Module -J104- must not be pulled out or raised up.
The seal on the ABS Control Module -J104- cannot be replaced.
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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.
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