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2025 Audi Q5/SQ5 Headlight Defective Warning TSB 2078609/5

Owners of 2025 Audi Q5 and SQ5 vehicles may see a "Left/right main beam headlight defective" warning message and DTC C12FC01. This TSB addresses the software issue causing the warning.

ByAhmet Topcu — Founder & Editor-in-ChiefAutomated summary2025 Audi Q5
2025 Audi Q5 — Audi Q5 headlight defective
Editorial illustration generated for this article.
C12FC011392722078609/5PSS 20781822079690 00Left/right main beam headlight defective. See owner's manualLED channel 4, electrical faultAudi Q5 headlight defectiveAudi SQ5 headlight defectivelight control unit 0029
Audi SQ5
2025

Owners of certain 2025 Audi Q5 and SQ5 models may encounter a dashboard warning message stating, "Left/right main beam headlight defective. See owner's manual." This issue, which can trigger the DTC C12FC01, indicates a software-related problem rather than a physical malfunction of the headlights. Audi has released Technical Service Bulletin (TSB) 2078609/5 to provide guidance for technicians on how to resolve this specific concern.

This TSB, released on February 19, 2026, and last revised on December 13, 2025 (Revision 4), clarifies that the warning is due to a software anomaly. It also supersedes a previous bulletin, PSS 2078182, which covered the same warning lamp issue in the instrument cluster. The primary solution involves a software update to the vehicle's control modules.

Symptoms

If your 2025 Audi Q5 headlight defective warning appears, you will typically observe the yellow warning message "Left/right main beam headlight defective. See owner's manual" displayed in the instrument cluster while driving. While this warning is active, there are no functional restrictions or performance limitations with the main beam headlights themselves. The warning lamp may disappear after switching the ignition off and then on again, but it often reappears intermittently during subsequent drives.

Fault Codes / DTCs

When diagnosing this issue, technicians will likely find Diagnostic Trouble Code (DTC) C12FC01 stored in the vehicle's diagnostic system. This specific code is identified as "LED channel 4, electrical fault" with symptom code 139272. The fault is typically found in diagnostic address 0029, which corresponds to the Left light control unit, and/or diagnostic address 0039, which corresponds to the Right light control unit. Despite the

Bu TSB'nin diğer revizyonları

What Audi Q5 owners report

Counted from the records in our database across 18 model years.

1,386
Owner complaints
35
Recalls
4,663
Service bulletins
68
Crashes reported
13
Fires reported
63
Injuries reported

The 2025 model year

46 complaints, the 12th most of 18 model years on file. Owners reported 3 crashes, 0 fires and 3 injuries for this year, which also has 1 recall on file.

Electrical System, the system this article covers, accounts for 230 of 1,386 complaints (17%), including 21 for 2025.

Complaints by model year

Model years with the most complaints for the Audi Q5
2010100
2011143
2012168
201392
2014106
2015100
201678
2018209
202174
202546

Most-reported systems

  1. Engine — 338
  2. Air Bags — 259
  3. Electrical System — 230
  4. Fuel/Propulsion System — 140
  5. Steering — 99

Latest recalls for the 2025 model year

  • 26V266000 — Seat Belts (Apr 2026)
All 2025 recalls →

Recent owner reports about electrical system

The NEW vehicle keeps showing a warning light on the dash saying that the rear wheel bolts are loose two accidents have occurred in a 60 day period, the vehicle has been in for service multiple times and Audi has not found a fix for the safety light warning…

2025 Audi Q5 owner, Oct 2026

The 2025 Audi Q5 has a systemic problem with its Multi Meidia and driver assist features, such as cruise control, side mirrors, back up camera, directional maps, etc, which malfunction at inopportune times causing major distraction while driving.

2025 Audi Q5 owner, Jun 2026
Read owner complaints →

Complaints are owner reports filed with NHTSA. They are unverified, and counts depend on how many vehicles were sold, so they are not a failure rate.

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2025 Audi Q5/SQ5 Engine Warning Lamp TSB 2081184/1

A Technical Service Bulletin (TSB 2081184/1) has been issued for 2025 Audi Q5 and SQ5 models regarding an illuminated engine warning lamp or non-functional air conditioning. This issue is linked to DTCs U366500, P2D8800, or P2D8B00, caused by an incorrectly fitted earth connection.

2025 Audi Q5/SQ5 Door Cannot Be Opened From Outside

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