A5 Alternator Symptoms: Multiple Electrical Problems Fix

I had a very similar issue with my 2019 Audi A4 last winter. With moderate experience working on cars, I initially thought it was just a battery problem, but the symptoms matched what you're describing, weak starts, flickering lights, and battery warnings. The alternator was indeed failing, which was confirmed when the workshop tested the charging system. The alternator replacement took about 4 hours of labor since they needed to remove several components to access it properly. Total cost was 960 Euro including parts and labor. Before committing to an alternator replacement, make sure to get the charging system properly tested. A failing alternator often means the serpentine belt needs inspection too, as it drives the alternator. In my case, they also checked the belt tensioner while doing the work. To help diagnose your specific case, could you share: Current mileage on your A5, When did these symptoms first appear, Whether the car won't start completely sometimes, If the battery is original or has been replaced before, Any other electrical issues you've noticed This information would help determine if you're facing the same alternator issue I had or if it might be something else in the electrical system.

Last service was done at 39000 KM, and these issues started about 2 weeks ago. After running diagnostics, the alternator output showed irregular voltage patterns. When the car won't start, it makes a clicking sound typical of low battery voltage. The battery is original from 2021. The engine misfire warnings appeared recently, likely due to insufficient power supply. Also noticed the infotainment system out of nowhere rebooting and car electronics behaving erratically. The starter motor seems to struggle more each day. Current mileage is 41087 KM and honestly waiting for the workshop appointment next week is making me nervous about getting stranded somewhere.

Thanks for the additional details, those symptoms match exactly what I experienced. The clicking sound and irregular voltage patterns from diagnostics are textbook signs of alternator issues, just like what I faced with my A4. The engine misfire warnings you mentioned are definitely related, my car showed the same before the alternator replacement. When the alternator is failing, it causes inconsistent power delivery to the ignition system, triggering those misfire codes. Since your symptoms are progressing (struggling starter motor, system reboots), I would strongly advise minimizing driving until your workshop appointment. My alternator completely failed two days after similar symptoms, leaving me stranded. The repair cost on my A4 was typical for this issue, you should expect around 900-1000 Euro for parts and labor. The irregular voltage output you mentioned is particularly telling, this was the definitive test that confirmed my alternator issue. While waiting for the appointment, try to avoid short trips and unnecessary electrical loads. When they do the alternator replacement, make sure they check the serpentine belt condition too, mine showed wear from the failing alternator and needed replacement as well. The good news is that once replaced, the system should work perfectly again, all my electrical issues, including the engine misfire warnings and erratic electronics behavior, resolved completely after the repair.

Given your diagnostics results and my symptoms timeline, I feel quite certain now that its the alternator. The clicking sound during start attempts and voltage drop patterns match perfectly with what you experienced. Based on your repair experience, I will set aside around 1000 Euro for the fix. Really appreciate knowing the actual repair time and costs, helps set realistic expectations for next week's appointment. The progressive nature of my issues, from initial battery low warnings to now having a struggling starter motor and system reboots, follows the same pattern you described. I will minimize driving until the appointment and avoid short trips that might strain the charging system further. Will make sure they inspect the serpentine belt during the alternator replacement. Good to hear all your electrical problems resolved completely after the repair. Thanks for sharing your experience, it has helped confirm my suspicions about the alternator being the root cause.