2021-2026 Audi Adaptive Light System Fault C12B3FA TSB

Audi has issued Technical Service Bulletin (TSB) 2054202/7, released on March 27, 2026, to address an intermittent "Audi adaptive light system fault" and other driver assistance system malfunctions. This TSB applies to various 2021-2026 Audi models and provides guidance for diagnosing and resolving the Diagnostic Trouble Code (DTC) C12B3FA.

This communication aims to help technicians and owners understand the root cause and appropriate repair procedures for the Audi adaptive light system fault and related issues, preventing unnecessary parts replacement.

Symptoms

Owners of affected 2021-2026 Audi vehicles may notice that their driver assistance systems become unavailable. The instrument cluster may display one of the following warning messages:

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

Fault Codes / DTCs

When these symptoms occur, the control module for driver assistance systems, identified as J1121 (diagnostic address 00A5), may intermittently store the following Diagnostic Trouble Code (DTC):

Code	Description	Symptom Code
C12B3FA	Front camera for driver assist systems - communication fault	221189

Diagnosis and Technical Background

Audi's technical background for DTC C12B3FA indicates that this communication error in the J1121 driver assistance systems front camera may appear intermittently. It is often triggered by external influences, such as electromagnetic compatibility issues.

Important Warning: Do Not Replace This Part

Owners and technicians should be aware of a critical advisory from Audi regarding this issue:

"The replacement of the front camera for the assistance systems R242 does not solve this issue, even if suggested by the Guided Fault Finding."

This means that replacing the R242 front camera will not resolve the Audi adaptive light system fault and should be avoided to prevent unnecessary costs and repairs.

Repair Procedure Summary

The repair procedure outlined in TSB 2054202/7 involves checking the software version of the J1121 driver assist systems control unit (diagnostic address 00A5).

• If the software version is below SW0295: Technicians are instructed to follow TSB 2063497, titled "90 Driver assist systems with various malfunctions (aLDW performance, ACC inop when towing etc.) B200FF9 B200FF3 C123FB."
• If the software version is SW0295 or above: No further measures are necessary or available. The issue is expected to resolve itself after a bus sleep cycle and a subsequent restart of the J1121 control unit.

Warranty Information

Warranty claims for this issue are processed according to the Audi Warranty Policies and Procedures Manual. The Service Number for this bulletin is 9093, and the Damage Code is 0039. Claims should reference TSB 2054202/7. If the vehicle is outside of warranty, this Technical Service Bulletin is informational only.

NHTSA ID: 11030988