Replacing rear brake pads and rotors on an Audi often requires interacting with the Electronic Parking Brake (EPB) system through VCDS. While online resources like the Ross-Tech Wiki provide valuable guidance, discrepancies can arise due to variations in EPB modules. This article clarifies the differences between UDS and non-UDS EPB systems, focusing on the necessity of a Vcds Parking Brake Function Test.
The Ross-Tech Wiki instructions for the Audi A5 (8T) initially seemed incompatible with the VCDS interface encountered on a 2016 Audi S5 (8T). Instead of a group code input for opening the rear parking brake, a dropdown menu with different options was presented. Further investigation revealed that the A4 (8R/8K) instructions accurately reflected the S5’s VCDS configuration. Notably, the A4 procedure lacked a function test step, raising concerns about the correct approach for the S5.
VCDS Parking Brake Options
The discrepancy was resolved by consulting the video linked at the bottom of the A5 instructions page. This video highlights the existence of two EPB module types: UDS and non-UDS. The written A5 instructions pertain to the non-UDS module, while the video segment demonstrating the UDS procedure aligned perfectly with the S5’s VCDS interface. This confirmed the S5 utilizes a UDS EPB module.
This discovery led to two key questions: Does a UDS EPB system require a function test, and should discrepancies be expected in other control module settings? The video for the UDS procedure concludes with “End Lining Change Mode,” leaving uncertainty about the need for a subsequent function test. Conversely, the non-UDS procedure explicitly includes a function test. Understanding the rationale behind this difference is crucial. Furthermore, knowing whether other control modules might exhibit similar variations between UDS and non-UDS equipped vehicles is important for future maintenance and diagnostics.
While the video doesn’t explicitly mention a separate function test for UDS systems, it’s important to note that “End Lining Change Mode” itself involves a series of automated checks and adjustments within the EPB system. This process inherently verifies the functionality of the parking brake after a service procedure. Therefore, a dedicated function test, as seen in non-UDS systems, may be redundant in UDS equipped vehicles. The “Initiation” option observed in the VCDS dropdown menu for UDS systems likely performs a similar role, ensuring proper calibration and functionality.
Regarding discrepancies in other control modules, it’s plausible that variations may exist between UDS and non-UDS equipped vehicles. Consulting the appropriate Ross-Tech Wiki page for the specific model and year is always recommended to ensure compatibility and accuracy when using VCDS for diagnostics and maintenance. Always prioritize safety and consult with a qualified technician if uncertainties arise.
