2025 Audi A5/Q5/S5/SQ5 Driver Assist Systems Offline TSB

Audi has released Technical Service Bulletin (TSB) 2077141/3 to address concerns regarding multiple driver assist systems going offline in certain 2025 Audi A5, Q5, S5, and SQ5 models. This bulletin, with a release date of October 17, 2025, is a proactive measure for upcoming models, providing guidance for technicians on diagnosing and resolving issues related to the short-range radar system and associated fault codes like C12BFF2. This TSB addresses the specific issue of an Audi A5 driver assist systems offline condition.

This TSB specifically targets a functional issue related to both software and hardware within the vehicle's advanced driver assistance systems (ADAS). Owners of affected vehicles may notice various warning messages in their instrument cluster, indicating a malfunction or unavailability of critical safety features. Understanding the symptoms and the prescribed repair steps is crucial for maintaining the optimal performance and safety of your Audi.

Revision History

Technical Service Bulletin 2077141/3 has undergone several revisions to ensure comprehensive coverage and accuracy:

• Revision 3: Added models and revised the header. Included a reference to KD2 update. (Date not specified, but newer than 07/17/2025)
• Revision 2 (July 17, 2025): Revised header to include updated customer codes and models. Updated service instructions with a statement regarding launch vehicles.
• Revision 1 (March 06, 2025): Initial publication of the bulletin.

Symptoms and Instrument Cluster Messages

Owners of affected 2025 Audi A5, Q5, S5, and SQ5 vehicles may experience various driver assist systems becoming unavailable. These malfunctions are typically accompanied by specific warning messages displayed in the instrument cluster. The primary concern is the reduced functionality of key safety features that rely on the short-range radar sensors, leading to an Audi A5 driver assist systems offline state.

Customers may observe the following messages:

• "Rear turn assist: fault. You can continue driving. See owner's manual."
• "Lane change assist: fault. You can continue driving. See owner's manual."
• "Exit warning system: fault. You can continue driving. See owner's manual."
• "Rear cross-traffic assist: fault. You can continue driving. See owner's manual."
• "Proactive occupant protection: currently restricted. See owner's manual."
• "Active front assist: currently unavailable. See owner's manual."

These messages indicate that the respective driver assistance functions are not operating as intended due to the underlying radar sensor software error.

Diagnostic Trouble Codes (DTCs)

When diagnosing the Audi A5 driver assist systems offline condition, technicians will find specific Diagnostic Trouble Codes (DTCs) stored in the vehicle's control units. The primary DTC associated with this issue is C12BFF2, which indicates a radar sensor software error.

The TSB identifies the following diagnostic trouble codes and their associated diagnostic addresses:

Diagnostic Address	Diagnostic Trouble Code	Fault Symptom	Storage State
8109 - Short-range radar 1	C12BFF2	Radar sensors Software error detected	Intermittent
810A - Short-range radar 2	C12BFF2	Radar sensors Software error detected	Intermittent
810C - Short-range radar 4	C12BFF2	Radar sensors Software error detected	Intermittent
810B - Short-range radar 3	C12BFF2	Radar sensors Software error detected	Intermittent

It's crucial to note that the symptom number associated with DTC C12BFF2 determines the necessary action. The TSB specifies two symptom numbers:

• C12BFF2 (symptom number 1289): This indicates a functional issue that requires resolution as per the repair procedure.
• C12BFF2 (symptom number 1282): This entry does not lead to a customer complaint and can be ignored. No measures are necessary for this specific symptom number.

Important Warnings for Owners

Owners should be aware of a critical distinction regarding the diagnostic trouble code C12BFF2:

• NOTICE: The event memory entry "C12BFF2: Radar sensor software error detected" (symptom number 1282) does not lead to a customer complaint and can be ignored. NO measures are necessary. This means if your vehicle displays this specific symptom number, no repair is required.

Repair Procedure Summary

The repair for the Audi A5 driver assist systems offline issue, specifically when DTC C12BFF2 (symptom number 1289) is logged, involves either a software update or, if the update is not yet available, the replacement of specific control units.

1. Software Update Check: Technicians must first check if Technical Service Bulletin 2079690, titled "00 Combined software update 03.10.00/C (28.13.01) KD2," is applicable and visible for the vehicle. If it is, the combined software update "03.10.00/C (28.13.01) KD2" described in TSB 2079690 should be performed.

   • NOTICE: The combined software update described in TSB 2079690 will be released in stages for individual vehicle models/markets, depending on availability.

2. Control Unit Replacement (if software update is not available): If the combined software update is not yet available, and the event memory entry "C12BFF2: Radar sensor software error detected" (symptom number 1289) is logged, the relevant control unit must be replaced. The affected control units are:

   • "Short-Range Radar 3 & 4" aka (Lane change assist) control unit -J769-/-J770- (diagnostic address 810B/810C).
   • "Short-Range Radar 1 & 2" aka (Front left/right radar sensor) control unit for object detection -J1088-/-J1089- (diagnostic address 8109/810A).

Warranty Information

Warranty claims for this issue must adhere to the Audi Warranty Policies and Procedures Manual. The details for claiming this repair are as follows:

• Claim Type: If the vehicle is outside of any warranty, this Technical Service Bulletin is informational only.
• Service Numbers:
  • 9635 (-J769-/-J770-)
  • 9158 (-J1088-/-J1089-)
• Damage Code: 0039
• Labor Operations:
  • Remove and install object detection control unit: 9158 1960 (for one unit), 9158 2060 (for two units). Refer to SRT for associated operations.
  • Remove and install lane change assist control unit: 9635 1950 (for one unit), 9635 2050 (for two units). Refer to SRT for associated operations.
  • GFF / Guided Functions: 0150 0060. Time stated on the diagnostic protocol.
• Claim Comment: As per TSB 2077141/3.

Owner Action

If you own a 2025 Audi A5, Q5, S5, or SQ5 and observe any of the instrument cluster warning messages indicating an Audi A5 driver assist systems offline condition, it is recommended to contact your authorized Audi dealer. While some messages suggest you can continue driving, the loss of advanced driver assistance features can impact safety.

Provide your dealer with the exact warning messages you see and mention Technical Service Bulletin 2077141/3. The dealer will be able to diagnose the issue, check for applicable software updates (TSB 2079690), and perform any necessary control unit replacements under warranty if your vehicle qualifies.

NHTSA ID: 2077141/3