Audi RS6 Auxiliary Battery Mayhem: Electrical Crisis Fix

I had a similar issue with my 2014 Audi RS4 last winter and discovered it was indeed a battery failure affecting multiple systems. With some experience working on Audi electrical systems, I can share what worked for me. The symptoms match what you're describing, multiple error messages and low voltage issues during engine start. After seeing similar problems, I took my car to a specialized workshop where they performed a complete electrical diagnostic. They found that both the main and auxiliary battery were showing significant wear. The fix included a battery replacement for both units, plus a proper coding of the new battery to the vehicle management system. Total cost was 290 Euro for parts and labor. Before suggesting specific solutions for your case, could you provide: Current battery age for both main and auxiliary units, Specific error codes showing up, Whether issues occur more frequently during cold starts, If you notice dimming lights or other electrical fluctuations These details would help determine if you're facing the same underlying issue. Since battery-related problems can cascade into other systems, getting an accurate diagnosis is crucial to prevent potential damage to other electrical components.

Last service at 145268 KM Thanks for the detailed response. Based on your feedback, I checked both batteries. The auxiliary power unit is original from 2012, while the main battery was replaced in 2020. Error codes mainly point to low voltage and battery malfunction alerts: P0562 (System Voltage Low), P0620 (Generator Control Circuit), Multiple sporadic communication errors The car electronics issues definitely worsen during cold starts, with dashboard lights flickering and occasional navigation system restarts. Will get both batteries tested professionally before proceeding with replacements to confirm the diagnosis. The age of the auxiliary battery certainly suggests it could be the root cause.

Thanks for the additional details. Based on the age of your auxiliary battery and the error codes, this strongly points to what I experienced. The symptoms align perfectly with my RS4 case, especially the cold start issues and system voltage alerts. At 11 years old, your auxiliary battery is well beyond its typical service life. When my auxiliary battery failed, I noticed similar voltage drop issues affecting the power management system. The P0562 code is particularly telling, as it matches what my diagnostic revealed. The navigation restarts and flickering lights are classic signs of auxiliary battery failure affecting the overall electrical stability. The generator control circuit error (P0620) often appears when the power management system struggles to maintain proper voltage levels. After replacing both batteries in my case, all electrical issues resolved completely. No more error messages or system malfunctions. The engine start is now consistently strong, even in cold conditions. Would recommend getting a full diagnostic, but be prepared that both batteries might need replacement given their age. The main battery from 2020 could have degraded prematurely due to compensating for the failing auxiliary unit. Quick tip: Make sure the shop properly codes the new batteries to the vehicle management system, this was crucial for resolving all error codes permanently in my case.

Thanks for those insights. After reviewing all the error codes and symptoms, I'll schedule a diagnostic appointment this week. Given what you shared about your experience, I expect I'll need to replace both batteries despite the main one being relatively recent. The flickering electronics and error codes match your case exactly. The auxiliary power unit being original from 2012 was definitely pushing its luck. My car electronics issues during cold starts make perfect sense now, the aging auxiliary battery simply cant maintain proper voltage levels anymore. Will make sure they perform proper coding after battery replacement to avoid any lingering issues with the power management system. Expecting costs around 300 Euro based on your repair bill, which seems reasonable for fixing these widespread electrical problems. Appreciate the detailed guidance. This helped confirm my suspicions about the auxiliary battery being the likely culprit behind all these cascading electrical failures. Will update once the repair is complete.