Removing and installing ABS control unit J104 and ABS hydraulic unit N55, RHD vehicles with ABS Mark 70 (ABS/TCS) — VW

🧭 Before you start

Fits: VW Jetta VI (16, 2010–2018)

• Opens: brake fluid

Don't miss

• Disconnect battery earth strap for all further work. Before doing so, check whether a coded radio is fitted in the vehicle. If there is one, first find out what the anti-theft code is.
• Mark brake lines (A) and (B) coming from brake master cylinder.
• Mark, unscrew and seal brake lines (1) to (4).

📋 Procedure

1. ⚠ Do not interchange the brake lines when connecting tandem brake master cylinder to ABS hydraulic unit N55. Mark installation position before removing brake lines.Do not bend the brake lines in the area of the ABS hydraulic unit N55 — Read out and note code of ABS control unit J104. [Note: Disconnect battery earth strap for all further work. Before doing so, check whether a coded radio is fitted in the vehicle. If there is one, first find out what the anti-theft code is.]
2. ⚠ There is a danger of electronic components being destroyed when battery is disconnected.Take necessary measures before disconnecting battery. — Pull off engine cover upwards from fastening points (arrows)10Engine cover; Removing and installing engine cover.
3. Hold engine cover (3) at points (1) and lift it upwards in direction of (arrow).
4. Pull engine cover in direction of (arrow) towards front out of retainer (2).
5. Pull off engine cover in areas marked with (arrows).

6. Observe the indicated order, (1) to (4)10Engine cover; Removing and installing engine cover
7. Grasp under engine cover as far as possible.
8. If necessary, remove intake hose (2)24Air filter; Assembly overview - air filter housing.
9. To do this, loosen clamps (1).
10. Seal openings with engine bung setVAS 6122.
11. Release connector from ABS control unit J104 in (direction of arrow) and pull it off.
12. Press locking slide (2) downwards in direction of (arrow).
13. Release catch (1) of connector (3) on ABS control unit J104.
14. To do this, press catch (1) downwards in direction of (arrow).
15. Apply brake pedal depressorV.A.G 1869/2.
16. Pull off front left cap (1).
17. Pull off rear left cap (1).
18. Connect hose of bleeder bottle (1) to bleeder valve of front left brake caliper.
19. Open bleeder valve.
20. Connect hose of bleeder bottle (1) to bleeder valve of rear left brake caliper/wheel brake cylinder.
21. Open bleeder valve.
22. Depress brake pedal at least 60 mm using brake pedal depressorV.A.G 1869/2.
23. Close front left and rear left bleeder valves.
24. Unclip hydraulic line (1) from retainer (2)(arrows).
25. Place sufficiently lint-free cloths under ABS control unit J104 and ABS hydraulic unit N55.
26. Mark brake lines (A) and (B) coming from brake master cylinder.
27. Detach brake lines (A) and (B) from ABS hydraulic unit N55.
28. Seal threaded holes immediately using sealing plugs from the assembly part kit, part no. 5Q0 698 311.
29. Immediately seal brake lines with sealing plugs1H0 698 311 A or suitable plugs from engine bung setVAS 6122.
30. Mark, unscrew and seal brake lines (1) to (4).
31. Seal threaded holes immediately using sealing plugs from the assembly part kit, part no. 5Q0 698 311.
32. Immediately seal brake lines with sealing plugs1H0 698 311 A or suitable plugs from engine bung setVAS 6122.
33. Pull ABS hydraulic unit N55 together with ABS control unit J104 upwards out of the dampers in (direction of arrow).
34. Remove ABS hydraulic unit N55 together with ABS control unit J104. [Note: Do not remove sealing plugs from new ABS hydraulic unit N55 until respective brake line is about to be installed.If sealing plugs are removed too early from the ABS hydraulic unit N55, brake fluid can escape, and it can then no longer be guaranteed that the unit can be sufficiently filled and bled.]
35. ⚠ When installing, ensure that rubber dampers are not pressed out of bracket. After installation, check that the ABS hydraulic unit N55 is firmly seated, or malfunction can occur. — Connect battery Electrical system27Battery; Disconnecting and connecting battery.
36. Remove brake pedal depressorV.A.G 1869/2.
37. Bleed brake system .

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