ABS Hydraulic Unit With ABS Control Module

ABS Hydraulic Unit with ABS Control Module

• To remove, remove the coolant reservoir

Special tools, testers and auxiliary items required

• Vehicle diagnostic, test and information system (VAS 505 x)

• Brake pedal actuator (V.A.G 1869/2)

• Sealing plug repair set, part no. 1H0 698,311A

The hydraulic unit - 2 - with the control module - 3 - and electric connection - 1 - is inside the engine compartment, in the front and on the left side under the coolant reservoir.






Removing

• Read the DTC memory with the (VAS 505 x) before removing.

- Turn off the ignition and connect the (VAS 505 x) to the diagnostic connection.






• Switch on ignition

• DTC memory interrogated, errors shown corrected and DTC memory erased.

- Start the program in Guided Functions.

Brake lines must not be bent.

- Switch the ignition off.

- Install the (V.A.G 1869/2) between the brake pedal and the driver seat. Press the brake pedal 60 mm.






- Raise the vehicle.

- Connect the bleeder bottle hose to the bleeder screws on the left front and left rear brake calipers and then open the bleeder screw.

• This lowers the pressure in the hydraulic unit.

- Close the left front and left rear bleeder screw.

- Lower vehicle.

- Do not remove (V.A.G 1869/2).

- Remove the coolant reservoir.

- To protect against escaping brake fluid, place a lint-free rag in the area under the control module and hydraulic unit.

- Mark the brake lines.

- Remove the brake lines from the mounts.

- Remove all brake lines form the hydraulic unit - 2 -.






Do not bend the brake lines near the hydraulic unit.

- Seal brake lines and threaded holes with plugs from repair kit.

- Disconnect the connector - 1 - from the control module - 3 -.






• Make sure that no brake fluid enters control module connector housing. This could lead to corrosion of the contacts and thereby cause the system to fail.

• Clean a dirty connector housing thoroughly with compressed air.

- Remove the hydraulic unit and control module from the bracket.

Replace the control module:

• If (VAS 505 x) has determined that control module is faulty "Control Module Faulty".

• If there is visible damage to the control module housing or to the connector

Replacing the ABS control module (J104) => [ ABS Control Module ] ABS Control Module.

- Remove the bracket from the hydraulic unit.

The pump motor may not be separated from the hydraulic unit.

Installing

Installation is the reverse of removal, with special attention to the following:

• Do not remove sealing plugs at new hydraulic unit until the corresponding brake line is about to be installed.

• If the sealing plugs are removed too early, brake fluid can escape and unit may not be sufficiently filled or adequately bled.

- Attach the bracket to the hydraulic unit.

- Install the hydraulic unit and control module into the bracket in the vehicle.

• Moisten the rubber piece in the bracket with water to make it easier to install.

- Remove the plugs from the new hydraulic unit.

• First install all the brake lines into the hydraulic unit and then tighten them.

- Install all the brake lines.

- Tighten all the brake lines.

• By performing the output check diagnosis, it can be determined if the line connections were interchanged.

- Install the brake lines into the mounts.

- Install the coolant reservoir.

- Remove (V.A.G 1869/2).

- Bleed brake system. Refer to => [ Brake System, Bleeding ] Service and Repair.

- Start the program in Guided Functions on the (VAS 505 x) if the control module is replaced.

- Perform an output diagnostic test Guided Functions in (VAS 505 x) after attaching the brake lines.

Tightening Specifications






Make sure the brakes are working correctly before driving the vehicle for the first time.