Audi A5 Battery Gremlins Cause Multiple System Failures

During a similar situation with my Audi A3 2014 gasoline model, I experienced comparable battery failure symptoms. The warning lights, electrical glitches, and weak engine start were clear indicators of a failing power system. The diagnosis revealed two issues: The main battery had degraded significantly, showing low voltage during testing, and the alternator wasnt properly charging the system. These electrical problems typically cascade, affecting multiple vehicle systems simultaneously. The repair required a complete battery replacement and alternator check. The process involved: Full diagnostic scan, Battery load testing, Alternator output verification, Electrical system inspection, Replacement of the main battery, System reset and code clearing This was a serious issue that needed immediate attention, as continued operation could have led to complete electrical system failure or left the vehicle stranded. The auxiliary power systems in modern Audis are complex and interconnected, making proper diagnosis crucial. The symptoms you describe match exactly what I experienced before the repair. Getting a proper diagnosis from a certified technician who can perform a complete electrical system check would be the safest approach, rather than just replacing parts without thorough testing.

Thanks for your detailed response about battery malfunction issues. My problem sounds identical to yours. I eventually got it fixed but had to replace both the main and auxiliary batteries due to severe power management problems. Would you mind sharing what your repair costs were? In my case the diagnosis and replacement set me back around 850 Euro including labor. Also curious if you experienced any other electrical issues since the fix? My car has been running fine for 6 months now, but I keep monitoring the voltage levels just to be safe. The mechanic mentioned these battery failure symptoms are quite common in Audis of our generation once they pass 100000km. Did your technician say anything similar about expected battery lifespan?

After getting the auxiliary battery malfunction fixed by my mechanic last month, I can confirm it completely resolved the power management issues. The total cost was 290 Euro which covered both diagnosis and repair of the battery charging system. The car electronics are now working perfectly with no warning lights or startup problems. My mechanic actually mentioned its quite fortunate we caught the failing auxiliary power system early, as leaving it unfixed could have led to more expensive electrical repairs down the line. Regarding battery lifespan, modern Audis often show first signs of battery failure around 90000-100000km mark, though this varies based on usage patterns and climate conditions. The key is monitoring the engine start performance and watching for early warning signs in the electrical system. Your 850 Euro repair cost seems higher than average, likely because you needed both batteries replaced. Since my main battery was still good, I only needed the auxiliary system fixed which explains the lower cost. The important thing is that both our cars are running properly now with restored power management systems.

After dealing with constant voltage drop issues, I finally took my car to a specialist last week. The diagnostic testing confirmed both batteries were failing. The mechanic found the auxiliary battery was completely dead and the main battery was operating at 40% capacity. The repair process was straightforward but expensive. They replaced both batteries, ran a full system check, and cleared all error codes. The engine start is now much stronger and all electrical systems work perfectly. No more unusual error messages on the speedometer. My previous concerns about mechanics overcharging were unfounded this time. The shop provided detailed documentation of the voltage tests and explained every step. While 850 Euro was more than expected, seeing the improvement in how the car runs made it worth it. Been keeping an eye on the battery performance through my OBD scanner. All voltage readings have been stable for the past week. Definitely learned my lesson about waiting too long to address electrical issues.