2023-2026 Audi Adaptive Light System Malfunction TSB 2054202/6

Audi has issued Technical Service Bulletin (TSB) 2054202/6 to address an adaptive light system malfunction that may affect various models, including the 2023-2026 Audi e-tron, A6, A7, A8, Q7, and Q8. This bulletin provides critical information for diagnosing and resolving issues related to the adaptive light system, specifically when the diagnostic trouble code (DTC) C12B3FA is stored in the control module for driver assistance systems.

The TSB highlights that owners may experience various symptoms, including warning messages displayed on the instrument cluster, and clarifies the appropriate repair procedures based on the vehicle's software version. This ensures that technicians perform the correct steps to resolve the underlying communication error, preventing unnecessary part replacements.

Symptoms of the Adaptive Light System Malfunction

Owners of affected 2023-2026 Audi vehicles may notice several indicators pointing to an adaptive light system malfunction. The most direct signs are specific warning messages appearing on the instrument cluster, which alert the driver to a system fault. These messages are crucial for identifying the problem and include:

• "Audi adaptive light: system fault"
• "Audi pre sense: system fault"
• "Adaptive cruise assist: restricted"
• "Adaptive cruise assist: predictive control currently restricted"

Beyond these explicit warnings, drivers might also observe that the overall driver assistance systems are unavailable. The malfunction can impact various lighting and signaling functions, leading to incorrect operation or complete failure of components such as the automatic high beam control, cornering lamps, and the headlamp range control system. Additionally, issues with indicator display symbols for cornering lights, bulb failures, or high beam indicators may occur, signaling that the system is not functioning as intended. These symptoms collectively point to the underlying communication error addressed by TSB 2054202/6, affecting the Audi e-tron adaptive light malfunction.

Fault Codes and Diagnostic Information

The primary diagnostic trouble code (DTC) associated with this adaptive light system malfunction is C12B3FA. This code specifically indicates a communication error within the driver assistance systems' front camera. The diagnostic address for this component is 00A5, which corresponds to the front sensor for driver assistance systems.

When a technician scans the vehicle for fault codes, they will find DTC C12B3FA stored intermittently in the J1121 control unit, which is the control module for driver assistance systems. The TSB notes that this particular DTC is often accompanied by symptom code 221189. The technical background provided in the bulletin explains that this communication error can occur intermittently due to external influences, such as electromagnetic compatibility (EMC) issues. These external factors can disrupt the data flow between the front camera (R242) and the control module, leading to the reported malfunctions and the storage of DTC C12B3FA, contributing to the Audi e-tron adaptive light malfunction.

Diagnosis and Trigger Conditions

Diagnosing the Audi e-tron adaptive light malfunction primarily involves identifying the presence of DTC C12B3FA in the J1121 control unit. Technicians will connect to the vehicle's diagnostic system to retrieve stored fault codes. The intermittent nature of the communication error means that the fault may not always be active, but its presence in the fault memory is sufficient for diagnosis.

The TSB clarifies that the issue often manifests under certain conditions where external influences, particularly those related to electromagnetic compatibility, can interfere with the communication lines of the front camera for driver assistance systems (R242). This interference can cause temporary disruptions, leading to the system registering a communication fault. Therefore, the diagnostic process focuses on confirming the DTC and understanding that its intermittent appearance is a characteristic of this specific problem, rather than a sign of a persistent hardware failure.

Repair Procedure Summary

The repair procedure for the adaptive light system malfunction, as outlined in Audi TSB 2054202/6, depends on the software version of the driver assist systems control unit (J1121, diagnostic address 00A5). It is crucial to determine the current software version before proceeding with any repair steps.

For Software Version Below SW0295

If the vehicle's software version is below SW0295, technicians are instructed to follow a different Technical Service Bulletin: TSB 2063497. This older bulletin addresses various malfunctions related to driver assist systems, including issues with adaptive lane departure warning (aLDW) performance, inoperative adaptive cruise control (ACC) when towing, and other DTCs such as B200FF9, B200FF3, and C123FB. This indicates that for older software versions, the adaptive light system malfunction might be part of a broader set of issues requiring a more comprehensive update or repair as detailed in the superseded bulletin.

For Software Version SW0295 and Above

For vehicles with software version SW0295 or newer, the repair process is significantly simpler and more direct:

1. Delete the DTC: The primary step is to delete the diagnostic trouble code C12B3FA from the control module. This clears the fault memory and resets the system's error flags.
2. Resolution after DTC Deletion: The TSB states that after deleting the DTC, the concern is fixed and is unlikely to reoccur. This suggests that the communication error is often transient, and clearing the fault allows the system to re-establish stable communication.
3. No Further Measures: No additional measures or parts replacements are necessary. The issue is expected to resolve completely after a bus sleep cycle and a subsequent restart of the driver assist systems control unit (J1121, diagnostic address 00A5). A bus sleep cycle allows the vehicle's electronic control units to power down and reset, which can often clear temporary communication glitches.

Important Warnings for Owners and Technicians

Audi Technical Service Bulletin 2054202/6 includes a critical warning that directly impacts diagnostic and repair decisions. This warning aims to prevent unnecessary and ineffective repairs, saving both time and cost.

NOTICE: The replacement of the front camera for the assistance systems R242 does not solve this issue, even if suggested by the Guided Fault Finding. Claims for replaced parts will be subject to review.

This notice is extremely important because diagnostic tools, such as Guided Fault Finding, might erroneously suggest replacing the front camera (R242) due to the communication error. However, the TSB explicitly states that this action will not resolve the problem. The root cause is a communication disruption, often due to external electromagnetic interference, rather than a faulty camera unit itself. Therefore, replacing the camera would be a wasted effort and an unnecessary expense. Audi's policy to review claims for replaced parts underscores the importance of following the TSB's specific repair instructions to address the Audi e-tron adaptive light malfunction correctly.

Owner Action

If you own a 2023-2026 Audi e-tron, A6, A7, A8, Q7, Q8, or any other affected model, and you experience any of the symptoms described, such as the "Audi adaptive light: system fault" message or issues with your driver assistance systems, it is recommended to contact an authorized Audi service center. Provide them with details of the symptoms you are observing and mention the potential relevance of Technical Service Bulletin 2054202/6.

While this TSB provides a clear repair path, it is classified as informational only and is not directly applicable to any Audi Warranty. This means that while the bulletin guides technicians on how to fix the issue, the cost of the repair may or may not be covered under your vehicle's warranty, depending on its specific terms and conditions. Always consult with your dealership regarding potential costs and warranty coverage for the Audi e-tron adaptive light malfunction.

Additional Information

All parts and service references provided within TSB 2054202/6 are subject to change or removal. Audi advises technicians to always check with their Parts Department and/or ETKA system for the latest information on parts and bulletins. Furthermore, it is essential to consult the Repair Manual for specific fasteners, bolts, nuts, and screws that may require replacement during any repair procedure. This ensures that all repairs are performed according to the most current manufacturer specifications and safety guidelines.

Source: NHTSA Manufacturer Communication 11025325