Working on the Electro-Mechanical Parking Brake (EPB)

From Ross-Tech Wiki

The following Tech Tip demonstrates the basic steps for working on the Electro-Mechanical Parking Brake (EPB) systems found in VW/Audi vehicles. This control module is accessed using address [53 - Parking Brake] electronics. (03-ABS for MQB platform cars).

The specific procedures and Basic Setting groups for each vehicle are listed using the main Diagnostic Procedures page and choosing the proper Brand and Chassis type. Vehicles that typically use the EPB system include:



Replacing the brake pads on Electro-Mechanical Parking Brake (EPB) equipped vehicles consists of 4 main steps:

Preparing the vehicle for the brake repairs

  • The EPB module is very sensitive to low voltage conditions! It is critical that a battery charger is properly connected and used for the duration of the rear brake job.
    • Vehicles with a battery mounted in the rear typically use a battery management module and it is essential to connect the charger properly at the charging posts as shown in this: Audi A8 (4E) example
  • Verify that the EPB system is working properly prior to the repair. This includes but is not limited to applying the normal hydraulic brake pedal and operating the EPB switch and running a complete Auto-Scan prior to repairs.
  • Make sure the system is fully assembled prior to repairs! This includes the calipers properly installed on the rotors with pads and all electrical components being connected.
  • The Parking Brake must be OFF prior to repairs or Basic Settings will not be possible!

Open Rear Parking Brake

  • The EPB system must be put into a service mode prior to the calipers being removed from the vehicle so the pistons can be pushed into the caliper housing. The specific Basic Setting groups vary depending on the vehicle and repair procedure to be performed.
  • Using VCDS you will click [Select] > [53 - Parking Brake] > [Basic Settings - 04] and TYPE in the specific Group Number -or- Select the appropriate option from the drop-down menu. Refer to the specific Diagnostic Procedures page for the vehicle in question. Click [Go!] and the brake calipers will open for repairs.
  • It is important to wait 30 seconds after the brake calipers and live readings stop moving before clicking [Done, Go Back] > [Close Controller, Go Back - 06] and removing the key from Ignition Switch.
  • The caliper pistons do not move back into the caliper, they are in a internally released position that allows the technician to push the pistons in as you would do with a conventional front brake job.
  • Perform the brake repairs and reassemble the system prior to moving on to the next step.


Close Rear Parking Brake

  • The EPB system service mode must be deactivated after the repairs.
  • Using VCDS you will click [Select] > [53 - Parking Brake] > [Basic Settings - 04] and TYPE in the specific Group Number -or- Select the appropriate option from the drop-down menu. Refer to the specific Diagnostic Procedures page for the vehicle in question. Click [Go!] and the brake calipers will close after repairs.
  • It is important to wait 30 seconds after the brake calipers and live readings stop moving before clicking [Done, Go Back] > prior to moving on to the next step.


Function Test

  • When applicable the EPB must be cycled On and Off prior to the Function Test. Do so using the button inside the vehicle while applying the normal hydraulic brake pedal.
  • Using VCDS you will click [Select] > [53 - Parking Brake] > [Basic Settings - 04] and TYPE in the specific Group Number. Refer to the specific Diagnostic Procedures page for the vehicle in question. Click [Go!] and the brake calipers will open and close 3 times taking up the excessive gap in between the piston and backing plate of the new pads.
  • It is important to wait 30 seconds after the brake calipers and live readings stop moving before clicking [Done, Go Back] > and checking [Fault Codes - 02].
  • The Brake job should be complete and the system should not have any fault codes stored.
    • If faults are stored use the Search feature in the upper right hand corner of all Ross-Tech Wiki pages to see if we have a page specific to the code(s) in question.
    • If 02596 - Rear Brake Pads Worn is stored in the (4E) Audi A8 see the Pad Thickness procedure.




The original "Avoid Damaging Rear Calipers" Tech Tip First appeared in Motor Magazine, June 2008. Copyright © 2000-2010 by Ross-Tech LLC. It is available in the downloadable .pdf format using this link to our Advertising Page.


Video Link

Electro-Mechanical Parking Brake (EPB), Rear Brake Service

Image4.jpg

https://www.youtube.com/watch?v=C9AcboaVGzY

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