Multiple Audi Error Messages Point to System-Wide Issue

I had a very similar issue with my 2012 S5 last year. As someone with moderate experience working on cars, these multiple system failures got me worried at first. After checking with my regular workshop and running engine diagnostics, they found that a software coding issue in the main control module was causing these cascade failures. The fault codes were pointing everywhere, but the root cause was actually incorrect vehicle coding after a previous repair. My symptoms matched yours exactly, warning lights, infotainment glitches, and instrument cluster going haywire. The repair involved a complete system recoding which cost 360 Euro. No parts needed replacement, just proper software configuration. Before suggesting specific solutions, could you share: Any recent repairs or battery disconnections? Are you able to read the specific fault codes with your OBD-II scan tool? Does the issue appear immediately after starting or does it occur while driving? Have you noticed any specific patterns when the errors appear? This information would help determine if your case is similar to what I experienced with the coding issue, or if it might be something else entirely.

Thanks for the detailed response. Last service was at 160000 KM with only a general inspection and oil change performed. Yes, I can confirm there was a battery replacement about 2 weeks ago. The error messages started appearing shortly after. Using my diagnostic scanner, I get multiple codes but the main one is U0100 pointing to lost communication with the engine control module. The issues appear right at startup and stay constant. No specific patterns noticed, but all warning lights come on simultaneously when it happens. I will try disconnecting the battery for 30 minutes to reset the system before taking it to a specialist. Looking at the fault codes, a recoding might indeed fix this as in your case.

Based on your battery replacement timing and the U0100 fault code, this definitely mirrors my experience. After comparing your symptoms with what happened to my S5, I am even more convinced we faced the same issue. The lost communication with the engine control module is often triggered when the battery change causes the main control unit to lose its coding. In my case, the scan tool revealed multiple communication errors across modules, but they were all stemming from this single root cause. The 30-minute battery disconnect might temporarily reset codes, but from my experience, you will need a proper system recoding to resolve this permanently. When my S5 had this issue, the temporary resets would work for a few starts before the malfunction indicator and other warnings returned. Since your fault codes are identical to what my vehicle displayed, I suggest going straight to a workshop capable of performing control module coding. This should cost around 350-400 Euro based on current rates, much less expensive than replacing components unnecessarily. The constant nature of your error messages, combined with their simultaneous appearance, strongly suggests a coding issue rather than actual component failures. Would recommend getting the coding done soon, as running with incorrect module configuration could potentially cause other issues.

Using your OBD-II scan tool details really helped narrow this down, that U0100 code perfectly explains the system-wide failures. Your suggestion about coding issues makes complete sense given the timing with my battery replacement. Had another chat with my mechanic and he confirmed the diagnostic scanner is showing exactly what you described, multiple communication errors originating from one root cause. Looking at the fault codes more closely, everything points to a coding reset that happened during the battery swap. Will skip the battery disconnect reset since you mentioned it only provides temporary relief. Already scheduled an appointment with a specialist workshop that can handle control module coding. The 350-400 Euro price range sounds reasonable compared to replacing parts unnecessarily. The engine light and warning messages are still constant but at least I know what to expect for the repair now. Really appreciate your insight on this, saved me from going down an expensive path of replacing components when it was just a coding issue all along.