Audi RS7 Alarm System Issues Linked to Failing Battery

I faced a very similar electrical issue with my 2019 Audi RS7 last winter. Having some experience with car battery problems, I can share what worked in my case. The symptoms started with unusual car alarm activations and persistent error messages. Initially tried basic troubleshooting but quickly realized the auxiliary battery system needed professional attention. The workshop diagnosed a failing auxiliary battery, which is quite common in these models after a few years. The battery problem was causing the alarm system to malfunction and storing those persistent error codes you mentioned. Total repair cost was 330 Euro, including: New auxiliary battery, System diagnostic, Alarm system recalibration, Error code clearing Before you head to a workshop, could you share: Current battery voltage readings if you have them, Age of the current auxiliary battery, Specific error codes showing up, Any other electrical issues you noticed This would help determine if your RS7 is facing the same issue or if there might be other factors involved. A voltage test of the auxiliary battery can be done at most auto parts stores if you want to confirm before paying for a full diagnostic.

Thanks for the detailed response. Last service was at 138000 KM and battery voltage readings are showing 11.8V. The battery check revealed the auxiliary battery is indeed original from 2021. Other electrical issues noticed include unusual central locking activation and occasional dashboard flickering when starting the car. The error code reader shows a B123456 related to battery system voltage being below threshold. The battery problem seems quite similar to what you described. Going to schedule a workshop visit this week as the constant car alarm glitches are becoming a real nuisance.

Based on the voltage readings and symptoms you shared, this is definitely matching the auxiliary battery failure pattern I experienced. The 11.8V reading is significantly below the optimal 12.6V we should see in a healthy system. The unusual central locking activation and dashboard flickering are telltale signs of a failing auxiliary battery. In my case, these symptoms progressively worsened until the alarm system completely stopped functioning. The error code B123456 confirms the battery signal is too weak, which matches exactly what my RS7 displayed before the repair. Since your auxiliary battery is the original from 2021, its likely reached the end of its service life, especially considering the mileage. The battery problem should be relatively straightforward to fix, similar to my repair. Make sure the workshop checks the main battery and charging system while they are at it, as a failing auxiliary battery can sometimes indicate broader electrical system issues. Quick heads up that you might want to disable the alarm system temporarily before heading to the workshop. This prevents those annoying false alarms during transit, which I learned the hard way.

The voltage readings and your repair experience match my situation perfectly. The 11.8V reading explains the constant electrical issues I've been dealing with. Will definitely take your advice about getting the main battery and charging system checked during the repair. Makes sense to look at the whole electrical system while they're working on the car alarm components. Good tip about disabling the alarm system before driving to the workshop. The battery alarm has been quite unpredictable lately, so that should help avoid any embarrassing situations on the way there. Just booked an appointment for tomorrow morning. The shop quoted around 350 Euro for a complete auxiliary battery replacement and system diagnostic, which seems reasonable based on your repair costs. Really appreciate you sharing your experience with such similar battery problems. Having this information makes me much more confident about the repair process and what to expect.