ABS Control Module (J104) and ABS Hydraulic Unit (N55)
ABS Control Module (J104) and ABS Hydraulic Unit (N55)
Special tools, testers and auxiliary items required
• Torque Wrench (V.A.G 1331)
• Torque Wrench (V.A.G 1410)
• Brake Pedal Actuator (V.A.G 1869/2)
• Vehicle Diagnosis, Testing and Information System (VAS 5051)
Plug (1H0 698 311 A)
Install the transportation protection after removing the ABS hydraulic unit.
The warranty on the ABS hydraulic unit will not be honored if there is no transportation protection.
1 Transport protection for valve domes (foam)
2 Sealing plugs M10
3 Sealing plugs M12
Removing
Component location:
The ABS control module is attached to the ABS hydraulic unit and is located inside the engine compartment on the right side.
1. ABS hydraulic unit with ABS Control Module
2. Brake booster with tandem master cylinder
Do not bend the brake lines near the ABS hydraulic unit!
- Get the coding from the ABS control module and write it down.
Use the (VAS 5051).
• Chassis
• Brake System
• Anti-lock braking system ABS/ASR Mark 70
• Function
• Check coding in the ABS control module J104
- Disconnect the battery.
Diesel engines with particulate filter
- Remove engine cover.
- Remove the toothed belt guard and the clips - arrows -.
- Remove the plenum chamber cover.
- Remove the plenum chamber bulkhead.
- Release and remove connectors - 1 - through - 3 -.
- Remove the particulate filter bracket screw - 1 -.
- Raise the vehicle.
- Loosen and remove the turbocharger/particulate filter clamp - 1 -.
• The illustration shows the clamp screw - 1 - from underneath. In some cases, this can be installed from the top.
- Remove exhaust system bracket from subframe- arrows -.
- Remove the bolts - 1 - and remove the driveshaft cover - 2 -.
- Unbolt the right driveshaft from the flange, lay it down and secure it.
- Loosen the double clamp on the exhaust pipe and push it toward the rear.
- Remove the nuts - 1 - and lower the particulate filter.
- Remove the nuts - 2 - and remove the particulate filter bracket - 3 -.
- Lower the particulate filter just enough so that it touches the steering gear.
• While lowering the particulate filter, pay close attention to the cable, the exhaust gas temperature sensor 1 and the heated oxygen sensor to prevent damage.
Continuation for all vehicles
- Remove the nuts - 1 - and remove the heat shield - 2 -, if equipped.
- Disconnect the connector from the ABS control module - in direction of arrow -.
- Insert (V.A.G 1869/2).
- Attach the bleeder bottle bleed hose - 1 - to the left front brake caliper bleed valve.
- Open the bleed valve.
- Attach the bleeder bottle bleed hose - 1 - to the brake caliper bleed valve/left rear brake cylinder.
- Open the bleed valve.
- Depress the brake pedal at least 60 mm with the (V.A.G 1869/2).
- Close left front and left rear bleeder valves.
Do not remove (V.A.G 1869/2).
- Place a lint-free cloth under the ABS control module and the ABS hydraulic unit.
Make sure no brake fluid gets onto contacts.
- Mark the master brake cylinder lines - A - and - B - and disconnect from the ABS hydraulic unit.
- Seal brake lines and threaded holes with sealing plugs (1H0 698 311 A).
- Mark brake lines - 1 - through - 4 - and then remove them.
- Mark brake lines (brake caliper) - 1 - to - 4 -, unscrew and seal.
- Remove the ABS hydraulic unit and the ABS control module in - direction of arrow - and pull upward out of the shock absorbers.
Installing
Install in reverse order of removal. Note the following:
• Remove the plugs on the new ABS hydraulic unit only when installing the brake line.
• Brake fluid will leak out if the plugs are removed too early from the ABS hydraulic unit. The system will then not have sufficient brake fluid and will not adequately bled.
When installing, make sure the damper rubber is not pushed out of the console. Make sure the ABS hydraulic unit is secure after installing it otherwise malfunctions can occur.
Vehicles with diesel engine and a particulate filter
• Replace the seals, self-locking nuts and the particulate filter clamp.
• Reinstall the cable ties and wires back in their original location.
• Pay attention to the installation sequence.
Installation sequence
1 Place the particulate filter on the turbocharger.
2 Loosely tighten down the clamp - 1 -.
3 Screw on bolts - 2 - through - 5 - loosely.
• It must still be possible to shift the particulate filter and bracket.
4 Tighten the clamp - 1 -.
5 Install bolts - 2 - and - 5 - and tighten.
6 Install bolts - 3 - and - 4 - and tighten.
Continuation for all vehicles
- Connect the battery.
- Remove (V.A.G 1869/2).
- Bleed the brake system. Refer to => [ Brake System, Bleeding ] Service and Repair.
If a new ABS control module was installed, it must be coded.
Use the (VAS 5051).
• Chassis
• Brake System
• Anti-lock braking system ABS/ASR Mark 70
• Function
• ABS Control Module J104, coding
Tightening Specifications
