2025 Audi Q5 Headlight Defective Warning TSB

Owners of the 2025 Audi Q5 may encounter an intermittent warning message in their instrument cluster stating, "Left/right main beam headlight defective. See owner's manual". This message, while concerning, often does not indicate an actual functional problem with the headlights. Audi Technical Service Bulletin (TSB) 2078609/1 has been issued to address this specific concern, identifying it as a software-related issue.

Symptoms

The primary symptom of this issue is the appearance of the yellow warning message "Left/right main beam headlight defective. See owner's manual" in the instrument cluster while driving. This warning is typically intermittent; it may disappear after the ignition is cycled off and on, only to reappear later. Importantly, despite the warning, the main beam headlights usually continue to function without any restrictions or performance degradation. This indicates a reporting error rather than a physical component failure.

Fault Codes / DTCs

When this warning appears, a diagnostic scan of the vehicle's systems will likely reveal the event memory entry C12FC01 LED channel 4, electrical fault, symptom 139272. This fault code is typically logged in diagnostic address 0029 (Left light control) and/or 0039 (Right light control). The presence of C12FC01 confirms the software-related nature of the problem, specifically pointing to an electrical fault within the LED channel of the headlight system, even if the physical light is working correctly, leading to the Audi Q5 headlight defective message.

Technical Background

Audi has determined that the "Left/right main beam headlight defective. See owner's manual" warning is a result of a software issue within the vehicle's control systems. This means the problem is not due to a faulty hardware component but rather an incorrect interpretation or reporting by the software managing the headlight functions. An optimized software solution has been developed to correct this anomaly.

Repair Procedure Summary

The resolution for the intermittent "Left/right main beam headlight defective. See owner's manual" warning involves updating the vehicle's software. This software update is designed to correct the underlying issue that causes the erroneous fault message. Technicians will need to perform a software update flat rate operation, identified by labor operation code 0151 0040, which accounts for 50 Technical Units (TU). Additionally, charging the battery (labor operation 2706 8950) may be required during the update process to ensure stable voltage. For vehicles where this TSB applies, it is crucial to check for the availability and visibility of TSB 2077960, titled "00 Combined software update 03.01.00/C (28.11.01) KD1**," as this bulletin describes the specific software update procedure to be performed.

Important Warnings

Owners and technicians should be aware of several critical points regarding this Technical Service Bulletin 2078609/1:

• This bulletin may apply to vehicles still within the new model launch repair authorization period. For such vehicles in the launch phase, workshops must create a case with the Technical Assistance Center (TAC) to obtain repair authorization. The TSB number 2078609/1 must be referenced in the first line of the TAC case.
• The software update described in TSB 2077960 will be released in stages for individual vehicle models and markets, depending on availability. This means the update might not be immediately accessible for all affected vehicles.
• If the vehicle is outside of any warranty, this Technical Service Bulletin is for informational purposes only, and the repair may not be covered free of charge.

Warranty Information

For vehicles covered under warranty, claims for this software update should be submitted in accordance with the Audi Warranty Policies and Procedures Manual. The Service Number associated with this repair is 9407, and the Damage Code is 0039. If the vehicle is no longer under warranty, the information provided in TSB 2078609/1 serves as guidance, but the cost of the repair may fall to the owner.

Source: NHTSA ID 11022680