Audi A2 No-Start Issue: ECU Failure Investigation

I had a really similar problem with my Audi A3 1998 gasoline model. Based on some experience working on cars, I can share what helped fix this issue. The engine light coming on before the no-start condition was exactly what happened to me. After taking it to the workshop, engine diagnostics revealed it wasnt actually an ECU issue or engine software problem, turned out the battery cable connections were badly corroded and not making proper contact. The workshop cleaned all battery terminals and connections, properly secured them, and applied anti-corrosion coating. Total cost was 155 Euro including diagnostics. The engine surge and starting problems completely disappeared after this fix. These symptoms can point to various issues though. Could you share: Any clicking sounds when turning the key? Does the dashboard light up normally? Have you noticed any intermittent electrical issues before this? When was the last time the battery connections were checked/cleaned? This information would help determine if your issue matches what I experienced or if its something different requiring other diagnostics.

Last service done at 146742 KM. Thanks for sharing your experience. When turning the key there are no clicking sounds at all, completely silent. Dashboard lights work fine and I have not noticed any electrical problems before. The battery connections were never checked as far as I know. Given the similar symptoms, I will have the battery connections inspected first before exploring more complex engine software or ECU issues. The engine light is still on though, will this clear itself once the connections are fixed or will it need resetting? Also wondering if the engine surge I experienced right before the complete no-start could be related to poor battery connections or if this points to a different problem?

Thanks for those details. Your symptoms sound nearly identical to what I experienced with my A3. The complete silence when turning the key strongly suggests electrical connection issues, just like my case. The engine surge you experienced before the no-start is also typical of failing electrical connections, as they get worse, they can cause inconsistent power delivery to the starter and fuel system before failing completely. The engine light will likely need manual clearing after fixing the connections. When my A3 had this issue, the engine diagnostics showed several stored fault codes due to the unstable power supply, but they were all related to the poor connections rather than actual engine control issues. My mechanic suggested a full electrical system inspection schedule every 60000km to prevent these issues. A thorough battery connection service usually includes: Terminal cleaning and reconditioning, Cable inspection and tightening, Anti-corrosion treatment, Connection resistance testing Total repair time was about 1 hour. Just make sure they perform proper engine diagnostics first to confirm no underlying ECU failure is present. Even with the diagnostic fee, this fix should cost significantly less than replacing electronic components. If cleaning the connections doesnt resolve the issue, we can explore other potential causes, but start with the simplest solution first.

Thanks for the detailed electrical advice. You know what, I just booked it in for next week to have those connections checked. Given how similar our problems sound, especially with the engine surge and complete silence when starting, I really hope its just corroded battery connections like in your case. The mechanic quoted 180 Euro for full diagnostics and electrical system inspection. If thats all it needs, it will be a relief compared to ECU repairs. They mentioned theyll clear any engine fault codes after fixing the connections. Will update once I get the results from the workshop. If its not the connections, at least the engine diagnostics should point us in the right direction. Really hoping to avoid any major electronic repairs. Just one last thing, did you need to replace any cables in your case or was cleaning the connections enough to fix the engine light and starting issues?