Removing and installing ABS control unit J104/ABS hydraulic unit N55, vehicles with 6-cyl. petrol engine — VW

🧭 Before you start

Fits: platform codes A32, A33

• Opens: brake fluid

Don't miss

• Separate connectors 20Separating connectors.
• Ensure no brake fluid gets onto contacts.
• First, mark the two brake lines (A) and (B) coming from brake master cylinder.
• Mark and unscrew brake lines (1) to (4).
• Before installing holder of ABS hydraulic unit N55 on bracket, spray rubber dampers with silicone lubricantD 007 000 A2.

📋 Procedure

1. Use to read code of ABS control unit J104 and note it.
2. Disconnect battery Electrical system27Battery; Disconnecting and reconnecting battery.
3. Release connector (2) at transfer point of fuel line and pull it off. [Note: Separate connectors 20Separating connectors.]
4. Release connector (2) at activated charcoal filter solenoid valve 1N80(1) and pull connector off.
5. Pull activated charcoal filter solenoid valve 1N80 off bracket (1).

6. Lay activated charcoal filter solenoid valve 1N80(1) with wiring to one side.
7. Unclip wiring harness (3) from water pipe (arrows) and lay aside.
8. Loosen clip (2) on water hose at coolant reservoir (3).
9. Clamp off water hose using hose clamps to 25 mm diameter3094.
10. Pull water hose off coolant expansion tank (3).
11. Unbolt water pipe (1) from cylinder head (arrows) and lay aside.
12. If fitted, unscrew nut (1) and remove heat shield (2).
13. Release connector from ABS control unit J104 in (direction of arrow) and pull it off.
14. Apply brake pedal depressorV.A.G 1869/2.
15. Connect bleed bottle bleed hose (1) to bleed valve of front left brake caliper.
16. Open bleed valve.
17. Connect bleed hose of bleed bottle (1) to bleed valve of rear left brake caliper.
18. Open bleed valve.
19. Depress brake pedal at least 60 mm using brake pedal depressorV.A.G 1869/2.
20. Close front left and rear left bleeder valves.
21. Place sufficiently lint-free cloths under ABS control unit J104 and ABS hydraulic unit N55. [Note: Ensure no brake fluid gets onto contacts.]
22. First, mark the two brake lines (A) and (B) coming from brake master cylinder.
23. Detach brake lines from ABS hydraulic unit N55.
24. Seal brake lines and threaded holes immediately using sealing plugs1H0 698 311 A or sealing plugs5Q0 698 311.
25. Mark and unscrew brake lines (1) to (4).
26. Seal brake lines and threaded holes immediately using sealing plugs1H0 698 311 A or sealing plugs5Q0 698 311.
27. Turn hexagon fitting bolt out of retainer (arrow).
28. Pull ABS hydraulic unit N55 together with ABS control unit J104 and side bracket out of rubber dampers of bracket in (direction of arrow).
29. Turn ABS hydraulic unit N55 with ABS control unit J104 on its head.
30. Unbolt bracket from ABS hydraulic unit N55 in engine compartment and remove.
31. Remove ABS hydraulic unit N55 together with ABS control unit J104. [Note: Remove sealing plugs from new hydraulic unit only when the corresponding brake line is to be fitted.If sealing plugs are removed too early from the hydraulic unit, brake fluid can escape, and it can then no longer be guaranteed that the unit can be sufficiently filled and bled.When installing the hydraulic unit, ensure that rubber dampers are not pressed out of bracket.]
32. Before installing holder of ABS hydraulic unit N55 on bracket, spray rubber dampers with silicone lubricantD 007 000 A2.
33. Using assembly toolV.A.G 1410/8, carefully fit brake lines.
34. Connect battery Electrical system27Battery; Disconnecting and connecting battery.
35. Remove brake pedal depressorV.A.G 1869/2.
36. Bleed hydraulic system .
37. Code control unit J104 with in "Guided Fault Finding".

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