ABS Control Module -J104- /ABS Hydraulic Unit -N55-, REMOVING AND INSTALLING: Installing

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Install in reverse order of removal while noting the following:

NOTE:

For customer service, the hydraulic unit N55 is filled with brake fluid.

Remove the sealing plugs on the new hydraulic unit N55 when the corresponding brake line is going to be installed.

If the sealing plugs are removed from the ABS Hydraulic Unit -N55- before installing the corresponding brake line, the brake fluid will drain. If that is the case, sufficient brake system bleeding can no longer be ensured.

All the rubber buffers must be inserted in the bracket.

-- Press the hydraulic unit N55 with the control module J104 down into the bracket in the vehicle.

When pressing the ESP control unit into the bracket, counterhold the rubber buffers so they do not fall through.

-- Connect the brake lines according to the markings.

WARNING:

If the brake line connectors are replaced, an ABS/ESP system malfunction will register.

NOTE:

During the output diagnostic test mode it can be determined if the line connections were interchanged.

-- Tighten all the brake lines -arrow- on the hydraulic unit N55.

Fig 1: Identifying Brake Lines

Courtesy of AUDI OF AMERICA, LLC

Component		Nm
All brake lines at the hydraulic unit		14

-- Connect the electrical connector on the control module J104.

-- Press the locking bracket down until it engages audibly.

-- Press the securing clip -1- down and engage it.

Fig 2: Identifying Brake Lines

Courtesy of AUDI OF AMERICA, LLC

-- Remove the Brake Pedal Actuator VAG1869/2.

-- Bleed the brake system. Refer to HYDRAULIC SYSTEM .

-- After securing the brake lines on the hydraulic unit N55, perform output diagnostic test mode.

NOTE:

During the output diagnostic test mode it can be determined if the line connections were interchanged.

Use the vehicle diagnosis, testing and information VAS5051B or 5052 for this.

If ABS Hydraulic Unit J104 was replaced, it must be coded.

Use the Vehicle Diagnostic Tester to do so.

-- On display, select:

Suspension
Brake system
001 - OBD-capable systems
003- Brake electronics.

-- Select the following functions on the display:

ABS/ASR/ESP control module J104
ABS/ASR/ESP control module J104, functions
J104 Coding control module

The following sensors should also be calibrated after replacing control module J104.

Steering angle sensor G85
Transverse Acceleration Sensor -G200-
Longitudinal acceleration sensor G251

Use the Vehicle Diagnostic Tester to do so.

-- On display, select:

Suspension
Brake system
001 - OBD-capable systems
003- Brake electronics.

-- Select the following functions on the display:

ABS/ASR/ESP control module J104
ABS/ASR/ESP control module J104, functions.

-- Then perform the ESP driving and system test.