Audi Q4 Turn Signal Failure Triggers Multiple Errors

As an owner of a 2019 Audi e-tron who faced similar turn indicator issues last year, I can share my experience. I have some basic experience working on EVs, mainly routine maintenance. The symptoms you describe match what I encountered, error messages and malfunctioning turn signals. Initially, I also thought it was just a defective bulb, but after taking it to a certified workshop, they diagnosed a faulty cable connection in the indicator light system. The plug connection had developed a loose contact over time. The repair involved testing the automotive lighting components and ultimately fixing the connection issue. Cost me 95 Euro for the complete diagnosis and repair. The whole process took about 2 hours, and the turn indicator has worked flawlessly since. Before suggesting more specific solutions, could you share: Are both left and right indicators affected? Does the issue occur consistently or intermittently? Are there any visible signs of damage to the broken lens or exterior components? What exact error messages are you seeing? This information would help determine if your Q4 has the same underlying issue mine had.

Thanks for your detailed response about the turn signal issues. My car has 134903 KM and was last serviced 3 months ago. Looking at your questions, both indicators are affected intermittently, but the right side shows more frequent problems. The turn signal works about 60% of the time, then stops completely. There is no visible damage to the signal lamp housing or broken lens that I can spot. The error message reads Error: Light System Service Required. Worth noting that regular bulb replacement did not resolve the issue. The workshop initially suggested this as a quick fix, but the problem persisted. From what you described, it sounds like I might be dealing with a similar wiring issue rather than just a faulty indicator light.

Thanks for providing those details about your Q4s turn indicator problems. Based on the intermittent nature and the fact that bulb replacement didnt help, this definitely sounds similar to my e-tron issue. The error message Light System Service Required typically points to an electrical problem rather than just a defective turn signal lamp. In my case, the flasher relay was also tested as part of the diagnosis, but the root cause was indeed the wiring connection. The intermittent function you describe, working 60% of the time, is a classic symptom of a loose or corroded connector in the automotive lighting system. Since both your turn signals are affected but the right side shows more issues, the problem is likely at a main connection point rather than in the individual lamp assemblies. When my car was repaired, they found slight corrosion at the main harness connector that affects both sides of the indicator system. Given the mileage on your car and that regular maintenance hasnt solved it, I would strongly recommend having the wiring connections checked, particularly around the main harness and flasher relay area. The repair for my vehicle was straightforward once properly diagnosed, and the fix has remained solid for over a year now.

Thanks for sharing such detailed information about your e-tron experience. My situation does sound very similar. The error codes and intermittent turn signal behavior match exactly what you described. After reading about your wiring connection fix, I called my regular workshop to schedule a full electrical fault diagnosis. They confirmed they will check the flasher relay and all wiring connections in the indicator light system. The appointment is set for next week. The fact that your repair has lasted over a year gives me hope this wont be a recurring issue. The turn signal problems have been quite frustrating, especially since the basic bulb replacement didnt help. Good to know the complete diagnosis and repair was relatively quick in your case. Will post an update after the workshop checks the wiring connections and hopefully resolves my electrical issues. The cost estimate they gave me was around 120 Euro, which seems reasonable considering the diagnostic work involved.