Audi A8 Alarm System Failure After Mechanic Visit

Had a similar alarm control issue with my 2016 Audi A7 3.0T. Initially thought it was a battery issue, but diagnostic testing revealed a faulty alarm sensor in the front door. The alarm control module was getting incorrect signals, causing the system to malfunction. The immobilizer stayed functional, which was fortunate since that would have been a more complex repair. Main symptoms matched yours, no response from the optical locking system and error codes appearing on the dash. First steps should be: Check key fob battery, Test central locking function, Verify if comfort closing still works, Monitor if car alarm triggers accidentally The repair required replacing the door sensor unit and recoding the alarm control module. Not a major mechanical issue, but requires specific diagnostic equipment to properly reset the system. Took about 3 hours at the shop to complete the full repair and testing. This is typically not a DIY fix due to the coding requirements. Would recommend having it checked at a shop with proper Audi diagnostic capabilities since unusual alarm triggers or complete failure can leave your vehicle vulnerable.

Thanks for the detailed walkthrough. This matches exactly what I experienced with my A8. Finally got it fixed last month after dealing with unusual alarm system failures for weeks. Been meaning to ask, what was the total repair cost in your case? Mine needed both a new alarm sensor and control module reprogramming. Also wondering if you had any recurring issues since the fix? Want to know if I should watch out for anything specific with the alarm control setup going forward.

Since getting the alarm system fixed at the shop, everything has worked perfectly. The anti-theft system now functions as intended, with no recurring power failure or false alarms. The total repair came to 45 Euro, which covered both the programming work and getting the optical locking indicators working again. The security alarm responds correctly to all triggers now. Much cheaper than expected, especially since the original alarm sensor didnt need replacement, it just required proper coding to sync with the control module. The battery issue others mentioned wasnt the root cause in my case. If youre experiencing similar problems again, monitor if the alarm activates consistently when locking. A properly working anti-theft system should give clear indicator signals every time. So far, 6 months after the repair, no warning lights or error codes have returned. The central locking and comfort features all work reliably too.

Thanks for the input. After reading the suggestions here, I took my A8 to a certified shop last week. Turns out my anti-theft system had multiple issues. The tech found a failing alarm control module and a worn-out door sensor. Total repair cost was 680 Euro including parts and labor. More than I hoped for, but at least the power failure issues are gone now. The shop had the right diagnostic tools and fixed everything in one day. The car alarm works perfectly now, no more unusual triggers or error codes. Really glad I didnt try fixing this myself since the system needed complete reprogramming after the repairs. The immobilizer is working properly too, and all security features are back to normal. Definitely learned my lesson about using shops with proper diagnostic equipment for alarm system issues. Much better than my previous sketchy mechanic experience.