RSQ3 Alarm System Dead: Control Module Failure Alert

I had a similar issue with my 2017 RS3, the security alarm system suddenly stopped responding one day. Being somewhat experienced with basic car electronics, I first suspected a battery issue in the key fob, but that wasnt the problem. After checking the basic fuses, I took it to a workshop where they diagnosed that the alarm system needed recoding. The central locking indicators werent flashing because the immobilizer system had lost its programming settings. The fix was relatively straightforward, they reprogrammed the car alarm control module and synchronized it with the immobilizer. Total cost was 45 Euro for the diagnostic and reprogramming work. The whole process took about an hour. Before suggesting more specific solutions, could you share: Have you checked if the key fob battery is working properly? Are there any other electrical issues, like interior lights or power windows? Does your dashboard show any specific error codes? Have you recently had any work done on the electrical system? These details would help narrow down whether youre facing the same issue I had or if its something different with your alarm system.

Thanks for the detailed response. My latest service was just 2 weeks ago at 42130 KM. I checked all those points you mentioned, key fob battery is new, no other electrical issues present, and all systems work perfectly except the anti-theft system. The only error code showing is related to the alarm control module specifically. The immobilizer still works fine since the car starts without issues, which makes me think its isolated to the alarm sensor system. No recent electrical work has been done, though the battery was replaced during the last service. Your situation sounds very similar, especially the part about the central locking indicators not flashing. Would be great if the fix was as straightforward as reprogramming the alarm control module. Did you notice any signs of the issue returning after the initial fix?

Since I had the same issue with my RS3, I can confirm the fix has been stable with no recurring problems for over a year now. The symptoms you describe are nearly identical to what I experienced, especially with the immobilizer functioning normally while the alarm system remained inactive. The timing with your recent battery replacement is interesting, in my research after fixing my car, I learned that disconnecting the battery can sometimes cause the alarm control module to lose its programming. This explains why the car alarm system might stop working after a battery service. Given that your car shows the same symptoms and error codes as mine did, I strongly suspect youll need the same fix, reprogramming the alarm control module. The good news is that its typically a straightforward procedure and much cheaper than replacing hardware components. From my experience, make sure they: Check the connection between the alarm sensor and control module, Verify the central alarm control unit isnt physically damaged, Perform a full system reset before reprogramming, Test all alarm system functions after the repair If the workshop confirms its just a programming issue like mine was, you should expect similar repair costs around 45-60 Euro for the diagnostic and reprogramming work.

I really appreciate all the detailed feedback. The connection with the battery replacement during my recent service makes a lot of sense, I had no idea a power failure could affect the alarm control module programming this way. Given how similar the symptoms are, especially with the central locking indicators and alarm sensor issues, I feel more confident about what to expect at the workshop. Good to know the fix has been reliable for you with no false alarms or recurring problems. I will make sure they do a complete system check including the alarm control connections and full reset before reprogramming. The estimated cost range is much more reasonable than I initially feared, especially compared to replacing hardware components. Going to book it in tomorrow and will specifically mention the potential need for alarm control module reprogramming. Thanks for saving me some diagnostic time, its helpful knowing where to start, especially since the issue appeared right after that battery service.