2025 Audi Driver Assist Systems Offline C12BFF2 TSB

Audi has issued Technical Service Bulletin (TSB) 2077141/2 to address instances where multiple driver assist systems become unavailable in certain 2025 Audi A5, Q5, S5, and SQ5 vehicles. This condition is often accompanied by the diagnostic trouble code (DTC) C12BFF2, indicating a radar sensor software error. This TSB provides guidance for technicians on diagnosing and resolving the Audi driver assist offline C12BFF2 issue.

This bulletin, released on July 17, 2025, supersedes previous revisions and provides updated information regarding affected models and customer codes. It is crucial for owners to understand the specific conditions under which this DTC requires action.

Symptoms

Owners of affected 2025 Audi vehicles may notice various driver assist systems becoming unavailable. The following messages may appear in the instrument cluster:

• "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 functions such as lane change assistance, exit warning, cross-traffic assist, and automatic emergency braking may not be operating correctly or at all.

Fault Codes / DTCs

The primary diagnostic trouble code associated with this issue is C12BFF2. This code indicates a software error detected by the radar sensors.

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

Diagnosis and Trigger Conditions

Technicians can reproduce the complaint by checking the Short-Range Radar control units. Specifically, the DTC "C12BFF2: Radar sensor software error detected" is stored in the Short-Range Radar 3 & 4 control units (-J769-/-J770-) (diagnostic address 810B/810C) and in the Short-Range Radar 1 & 2 control units for object detection (-J1088-/-J1089-) (diagnostic address 8109/810A).

Important Warning for Owners: The TSB explicitly states that if the event memory entry "C12BFF2: Radar sensor software error detected" is logged with symptom number 1282, it does not indicate a customer complaint and can be ignored. No measures are necessary in this specific case. However, if the DTC C12BFF2 is logged with symptom number 1289, it requires attention.

Repair Procedure Summary

If the DTC "C12BFF2: Radar sensor software error detected" (symptom number 1289) is logged, the repair involves replacing the affected Short-Range Radar control unit(s). This procedure ensures the proper functioning of the driver assist systems and resolves the Audi driver assist offline C12BFF2 condition.

Required Parts and Labor Operations

For warranty claims, the following service numbers and labor operations are specified under TSB 2077141/2:

• Service Number 9635: For control units -J769-/-J770-
• Service Number 9158: For control units -J1088-/-J1089-
• Damage Code: 0039

Labor operations include removing and installing object detection control units or lane change assist control units. Specific labor operation codes are provided for single or dual unit replacements, as well as for Guided Functions (GFF).

Owner Action

If you own a 2025 Audi A5, Q5, S5, or SQ5 and are experiencing any of the described driver assist system malfunctions or instrument cluster warning messages, it is recommended to contact your authorized Audi dealer. Inform them about the symptoms you are observing. The dealer will perform a diagnostic scan to check for the presence of DTC C12BFF2. Ensure they differentiate between symptom number 1282 (which can be ignored) and symptom number 1289 (which requires repair). Repairs performed under warranty will be free of charge.

Important Warnings

• Do not replace components if C12BFF2 is logged with symptom number 1282. This specific variant of the DTC does not indicate a customer complaint and requires no action. Only C12BFF2 with symptom number 1289 warrants a repair.
• This TSB may apply to vehicles still in the new model launch phase. Workshops must create a Technical Assistance Center (TAC) case for repair authorization in such situations, referencing TSB 2077141/2.

Production Solution

Audi implemented a production solution for this issue starting in Calendar Week 36 of 2025.

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Source: NHTSA ID: 11021459, TSB ID: 2077141/2