Audi SQ8 Door Lock System Failure & Alarm Triggers

I had a similar issue with my S7 from 2021. Having moderate experience with car electronics, I initially tried basic troubleshooting but ultimately needed professional help. The problem turned out to be a faulty wiring harness connecting to the door sensor. The contact signal was intermittent, causing both the locking issues and false alarm triggers. The workshop performed a full diagnostic scan which revealed communication errors between the door control module and the central locking system. The repair involved replacing a section of the wiring harness and recalibrating the door sensors. Total cost was 95 Euro including diagnostics and labor. Since the fix, the system has worked flawlessly. For a more accurate diagnosis of your situation, could you provide: Does the issue affect all vehicle doors or just specific ones? Are there any warning lights on the dashboard? Does the central locking work with the physical key? Have you noticed any other electrical issues? These details would help determine if youre facing the same underlying cause or if its a different component causing the problem.

Thanks for sharing those details about the wiring harness. The issue affects all doors and no warning lights appear on the dashboard. The physical key works intermittently at best. The door latch mechanism feels normal when using it manually. After my last service at 150910 KM, I did notice the door switch acting slightly different, particularly the audible feedback when locking. The car alarm seems most sensitive on the passenger side, triggering about 50% of the time when using that door. I think I will need to get it properly diagnosed based on your experience, though hoping the fix might be simpler in my case given its a newer model.

Based on your description of the symptoms after the service interval, this sounds very similar to my experience, but with a slight variation. Since you mentioned the change in audible feedback and the specific alarm sensitivity on the passenger side, it might point to a calibration issue rather than the complete wiring harness replacement I needed. When my automatic locks started acting up, I also noticed the sound difference before the system failed completely. The fact that your physical key works intermittently suggests the door sensor system might still be partially functional, unlike my case where it failed completely. The 50% alarm trigger rate on the passenger side strongly suggests a door contact signal issue, but possibly just needing adjustment rather than replacement. The workshop might be able to recalibrate the door sensors and check the connections without a full harness replacement. For what its worth, even after my repair, I had them perform a complete sensor calibration which was included in that 95 Euro cost. Given your car is newer, you might want to have them check if theres a software update for the door control module first, as manufacturers sometimes release fixes for these electrical issues. Would be interested to hear what they find during diagnostics in your case.

Thanks everyone for the detailed responses. Your input has been really helpful. I took the car to the workshop today and the diagnosis revealed exactly what was suggested, a calibration issue with the door sensors following the recent service. The car alarm was triggering due to misaligned contact signals. The good news is theyaged to fix it with a recalibration of the door latch system and a software update to the door control module. Total cost came to 75 Euro which seems reasonable compared to a full wiring harness replacement. Just wanted to close the loop here in case anyone else faces similar vehicle door issues in the future. The key learning was that sometimes these automatic lock problems can be resolved with simpler fixes, though proper diagnosis is essential. The doors are now working perfectly, no more false alarms or locking issues. Thanks again for helping me narrow down the problem.