Audi A3 Key Fob Issues Point to Faulty Antenna System

As someone with some experience working on Audis, I faced a very similar issue with my 2018 Audi A4. The symptoms you describe match exactly what I encountered, particularly the keyless entry problems and radio signal issues. After multiple failed attempts to diagnose it myself, I took it to a workshop. They discovered a damaged cable connection at the antenna mount, which was causing interference with both the key fob signal and car radio reception. The antenna repair involved replacing the wiring harness connecting to the main antenna module. The complete fix, including labor and parts, cost me 95 Euro. The workshop completed the repair in about 2 hours, and all systems have worked flawlessly since then. To better assist with your specific case, could you provide: Which engine variant your A3 has, Whether you notice any warning lights on the dashboard, If the car radio is also showing reception problems, The specific error codes from your diagnostic scan The solution might vary depending on these details, as different A3 configurations can have slightly different antenna setups and wiring layouts.

Thanks for your input. My A3 has covered 127353 KM and just had its annual service last month. The radio signal issues started shortly after the service, which is interesting. After testing, I noticed the vehicle antenna signals are indeed weaker than normal, both the FM radio and key fob range have significantly decreased. A quick scan revealed error codes related to the automotive antenna system, pointing to signal interference. The dashboard occasionally shows a key not detected warning, even when the fob is inside the car. The radio reception drops completely in areas where it used to work fine. Looking at all the symptoms and your experience, it seems the antenna wiring might have been disturbed during the service. Would appreciate any advice on specific diagnostic steps before heading to a workshop.

Thanks for those additional details. The timing of these issues starting right after the service is a telling sign. In my case with the A4, I also noticed the problems emerged after some work was done near the antenna area. Based on your description of weakened vehicle antenna signals and the specific error codes, this really sounds like a classic case of antenna wiring damage. The key not detected warning combined with poor radio reception strongly suggests signal interference in the main antenna system. The good news is that antenna repair for these issues is usually straightforward. In my case, the workshop first performed a signal strength test to pinpoint the exact location of the interference. They found that the antenna wiring had been slightly pinched during previous work, causing intermittent connection issues. One quick test you can do: check if the signal problems get worse when driving over bumps or rough roads. In my car, this was a clear indicator of loose antenna connections. For an A3 with these symptoms, I would expect the repair costs to be similar to what I paid, around 90-100 Euro depending on whether they need to replace the entire antenna assembly or just repair the wiring. Definitely worth getting it checked soon, as these signal interference issues tend to worsen over time and could eventually affect other electronic systems.

Thank you for sharing those similar experiences. Your A4 case is particularly relevant since I also see increased signal interference when driving on uneven roads. I will try that quick test you suggested about checking for signal variations over bumps, that could really help pinpoint if the antenna mount is indeed loose. The fact that your repair cost around 95 Euro gives me a good baseline for what to expect. Given all these matching symptoms, the reduced car radio reception, key fob issues, and error codes, I feel more confident now that this is likely an antenna system problem rather than something more serious. I will schedule a workshop visit next week and specifically ask them to check the antenna wiring near where the service work was done. The clear connection between the service timing and the start of these signal interference issues seems too significant to ignore. Will make sure to request a proper signal strength test like you mentioned. Really helps knowing what tests to ask for and approximately what the antenna repair should cost. This gives me a much better position when discussing the repair with the workshop.