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.
Overview - Control Module And Hydraulic Unit
2025 Audi A4 Quattro PrestigeSECTION Overview - Control Module And Hydraulic Unit
Control Module and Hydraulic Unit
- Rubber Bushing
- Mounting Bracket
- Bolt
- Tighten in two steps alternating from side to side.
- 1. Step: 1 to 1.5 Nm (to position the seal)
- 2. Step: 2.5 Nm
- ABS Control Module -J104-
- If the ABS Control Module -J104- is faulty, it can be replaced separately.
- If the ABS Hydraulic Unit -N55- is faulty, it must be replaced together with the ABS Control Module -J104-.
- Refer to ABS Control Module -J104- / ABS Hydraulic Unit -N55-, REMOVING AND INSTALLING
- Can be replaced separately if faulty.
- Refer to CONTROL MODULE, SEPARATING FROM HYDRAULIC UNIT
- Refer to CONTROL MODULE, INSTALLING ON HYDRAULIC UNIT
- Brake Line
- To the brake caliper
- Do not change the bending shape.
- Replace a damaged or bent brake line
- 14 Nm
- ABS Hydraulic Unit -N55-
- If the ABS Control Module -J104- is faulty, it can be replaced separately.
- If the ABS Hydraulic Unit -N55- is faulty, it must be replaced together with the ABS Control Module -J104-.
- Brake Line
- From brake master cylinder to the hydraulic unit
- Do not change the bending shape.
- Replace a damaged or bent brake line
- 16 Nm
- Brake Line
- From brake master cylinder to the hydraulic unit
- Do not change the bending shape.
- Replace a damaged or bent brake line
- 14 Nm
- Bolt
- 25 Nm
ABS Control Module -J104-
Fig 2: Identifying Pressure Sensor Contact, Pressure Sensor, Seal, Valve Bodies And Pump Motor Contact
- Pressure Sensor Contact
- Do not touch the contacts
- The illustration depends on the model
- Pressure Sensor
- Must not be changed or damaged
- Cannot be replaced
- The illustration depends on the model
- Seal
- Do not remove or lift
- Cannot be replaced separately
- Valve Body
- Must not be damaged
- Do not use any tools
- Pump Motor Contact
- Must not be damaged
RENDER: 1.0x
NO RELATED
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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.