2025-2026 Audi A5, S5, A6 Side Assist Warning TSB

Audi has released Technical Service Bulletin (TSB) 2078803/4, last revised as Revision 4 on February 20, 2026, to address instances where the side assist system issues false warnings in 2025-2026 Audi A5, S5, and A6 vehicles. This bulletin provides a specific repair procedure to prevent these erroneous alerts.

Symptoms of False Side Assist Warnings

Owners of certain 2025-2026 Audi A5, S5, and A6 models may experience an issue where the side assist system generates warnings without an actual vehicle in the blind spot. The primary symptom reported by customers is the verbatim message "side assist issues warnings for no reason", accompanied by the "light in the exterior mirror on the corresponding side of the vehicle lights up" even when no other vehicle is present. This can be distracting and reduce confidence in the driver assistance system, potentially leading to confusion or missed actual warnings.

Diagnosis and Technical Background

Workshop technicians can typically reproduce the complaint during diagnostic checks. The root cause of this false warning condition has been identified as reflections occurring within the bumper carrier. These reflections can interfere with the side assist sensors, leading the system to incorrectly detect an object in the blind spot. This technical bulletin, 2078803/4, specifically outlines the steps to mitigate this issue by modifying the bumper carrier.

Important Warnings for Repair

Audi has provided specific instructions regarding the repair process to ensure efficiency and correctness, and to prevent unnecessary work:

• Vehicles with Towing Bracket: For Audi models equipped with a towing bracket, it is explicitly stated that "On vehicles with a towing bracket, it is not necessary to remove the rear bumper cover" during this repair. This instruction is crucial for saving significant labor time and complexity.
• Vehicles Without Towing Bracket: For vehicles not equipped with a towing bracket, technicians are advised to "seal off the openings on the top of the bumper carrier (see Figure 3). Please use a commercially available aluminum adhesive tape to do this." This highlights the need for additional sealing in these specific cases, beyond just the side openings.

Repair Procedure Summary

The repair outlined in Audi TSB 2078803/4 involves closing off specific openings on both sides of the bumper carrier. This modification is performed to prevent reflections from interfering with the side assist sensors, which are the cause of the false warnings.

For vehicles with a towing bracket, the repair involves modifying the bumper carrier by closing the openings using available caps or aluminum adhesive tape. As noted, the rear bumper cover does not need to be removed for this version of the repair. This streamlines the process considerably.

For vehicles without a towing bracket, the process is similar but may require additional steps. The openings on both sides of the bumper carrier are closed off using available caps or aluminum adhesive tape. Additionally, the openings on the top of the bumper carrier must also be sealed, using commercially available aluminum adhesive tape as depicted in Figure 3 of the technical bulletin. Depending on the specific configuration, removing and reinstalling the rear bumper cover may be necessary for access to perform this sealing. This procedure directly addresses the "Audi A6 side assist warning" problem by eliminating the source of the false reflections.

Required Parts

To perform this repair, specific parts are required depending on whether the vehicle is equipped with a towing bracket. These parts are designed to effectively seal the bumper carrier openings:

• For vehicles with a towing bracket:
  • Part number 8B3.907.753.A (required for both the left and right sides)
• For vehicles without a towing bracket:
  • Part number 8B3.907.753 (for the left side)
  • Part number 8B3.907.754 (for the right side)

Technicians should use the available caps or aluminum adhesive tape as specified in the bulletin to ensure a proper and lasting repair.

Warranty Information

This Technical Service Bulletin 2078803/4 outlines the specific warranty claim procedures for this repair. If the vehicle is outside of its warranty period, this bulletin serves as informational guidance only, meaning the repair cost may not be covered.

• Service Number: 9635
• Damage Code: 0010
• Labor Operations:
  • Vehicles with towing bracket: Modify bumper carrier (Labor operation code: 6350 5099, 30 Time Units)
  • Vehicles without towing bracket: Remove and install rear bumper cover (Labor operation code: 6369 19xx, refer to SRT for associated operations), Modify bumper carrier (Labor operation code: 6350 5099, 10 Time Units)

All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual to be processed correctly.

What Owners Should Do

If you own a 2025-2026 Audi A5, S5, or A6 and are experiencing false side assist warnings, where the "light in the exterior mirror on the corresponding side of the vehicle lights up" without an actual blind spot obstruction, you should contact your authorized Audi dealership. Reference Technical Service Bulletin 2078803/4 when discussing the "Audi A6 side assist warning" issue. The dealership will be able to diagnose the problem and perform the necessary repair to seal the bumper carrier openings, resolving the false warnings.

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Source: NHTSA ID: 11029391