2026 Audi A3, S3, RS 3 Driver Assist System Fault

Owners of 2026 Audi A3, S3, and RS 3 models may experience issues with their driver assist systems becoming unavailable. This can manifest through various warning messages appearing in the instrument cluster. The underlying cause for this Audi S3 driver assist fault has been identified as a software issue affecting the radar sensor control units.

This Technical Service Bulletin, TSB 2080141/1, provides a specific repair procedure for technicians to address these software-related malfunctions, ensuring the proper function of critical safety and convenience features in affected vehicles.

Symptoms of a Driver Assist System Fault

If your 2026 Audi A3, S3, or RS 3 is experiencing an Audi S3 driver assist fault, you might notice one or more of the following messages displayed in your instrument cluster:

• "Lane departure warning: fault. See owner's manual."
• "Exit warning system: fault. You can continue driving. See owner's manual."
• "Side assist: fault. You can continue driving. See owner's manual."
• "Distance warning: fault. Please contact workshop."
• "Active front assist: fault. Please contact workshop."

These messages indicate that various driver assist systems, which rely on radar sensors, are not operating correctly or are completely unavailable. The specific warning displayed can depend on the vehicle's equipment level.

Fault Codes and Diagnostic Information

When an Audi S3 driver assist fault occurs, technicians will typically find a specific event memory entry logged in the vehicle's diagnostic system. The primary diagnostic trouble code (DTC) associated with this issue is:

• C12BFF2: Radar sensor software error detected (symptom number 12583034)

This DTC is logged in the lane change assist control units (-J769- and -J770-, diagnostic addresses 810B/810C) and the front left/right radar sensor control units for object detection (-J1088- and -J1089-, diagnostic addresses 8109/810A). It's crucial to note that TSB 2080141/1 specifically applies only if this exact event memory entry is logged.

Repair Procedure Summary

The repair for this driver assist system fault involves a software-based solution, focusing on resetting and calibrating the affected control units. The procedure, performed by an authorized Audi technician using the ODIS-S diagnostic system, includes the following steps:

1. Self-diagnosis: The technician will initiate a self-diagnosis for the affected diagnostic addresses within ODIS-S.
2. Factory Reset: A "Reset to factory setting" routine will be performed in the basic settings of the control units.
3. Bus Sleep Cycle: The vehicle will be allowed to enter a bus sleep cycle, which is a state where electronic control units power down to conserve energy.
4. Module Activation: The affected diagnostic addresses will be fully activated using the "Replace control module test plan" Guided Function. It is important to note that this procedure does not require replacing any physical parts.
5. Second Bus Sleep Cycle: Another bus sleep cycle is required after the activation step.
6. Calibration: Finally, a calibration of the affected diagnostic address will be performed using the corresponding Guided Function to ensure proper operation of the radar sensors and associated driver assist systems.

Important Warnings for Owners

Owners should be aware of a critical detail regarding this repair: Do not replace any parts. The Technical Service Bulletin 2080141/1 explicitly states that the repair is software-based and involves resetting and calibrating existing control units, not replacing them. Attempting to replace parts will not resolve the underlying software issue.

Warranty Information

For vehicles still under warranty, this repair procedure, including the software reset and calibration, should be covered. However, if your 2026 Audi A3, S3, or RS 3 is outside of its warranty period, this Technical Service Bulletin is considered informational only, and any associated costs may not be covered. Audi's warranty claims are subject to review and audit by Audi Warranty, in accordance with their Policies and Procedures Manual.

Technicians will use specific service and damage codes for warranty claims related to this TSB. These include Service Numbers 9635 (for -J769-/-J770-) and 9158 (for -J1088-/-J1089-), and Damage Code 0039 for both sets of control units. Labor operations such as GFF / Guided Functions (0150 0010, 0150 0060) and Check vehicle (bus sleep mode) (0689 0199) are also specified.

What Owners Should Do

If you are experiencing any of the described driver assist system fault messages in your 2026 Audi A3, S3, or RS 3, it is recommended to contact an authorized Audi dealership. They can perform the necessary diagnostic checks to confirm the presence of DTC C12BFF2 and apply the software update and calibration procedure outlined in TSB 2080141/1.

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Source: NHTSA ID: 11026288