Audi A4 Battery Light + Power Loss Points to Alternator

I experienced identical symptoms with my 2003 Audi A6 2.4L last winter. The alternator was indeed failing, causing voltage drop across the electrical system. When tested, the alternator was only producing 11.2V instead of the required 13.8-14.4V. The symptoms started exactly as described, dim headlights, battery warning light, and difficult starts. The car would run fine for short trips but struggle after longer drives. A voltage test confirmed the alternator was not charging properly, and the battery was being drained during operation. This is a serious issue that needs immediate attention, as it can leave you stranded when the battery fully depletes. The alternator replacement required removing several components to access it, including the front bumper cover and timing belt components. The job also included replacing the serpentine belt and tensioner while everything was apart. The error code is likely P0562 (System Voltage Low) or similar charging system code. Getting this read will confirm the diagnosis. Would strongly recommend having it checked soon, as continuing to drive with a failing alternator can damage other electrical components and eventually cause complete engine shutdown while driving.

Thanks for sharing your experience with the alternator issue. Really useful details about the voltage readings and symptoms. I had my alternator replaced on my A4 about 6 months ago after similar problems. Curious how much you ended up paying for the alternator replacement and if any other electrical issues showed up afterward? My starter motor started acting up a few weeks after the fix, wondering if that could be related to running the car with a bad alternator for too long. The serpentine belt was pretty worn when they did mine, so they changed that too. Been running fine since, but good to hear about others experiences with these car electronics problems.

Had the alternator replacement done last week actually, total came to 960 Euro including parts and labor. The Generator faulty warning is now completely gone and the electrical system is working perfectly. No more dim headlights or car won't start issues since the repair. The mechanic confirmed the old alternator was only putting out around 11V, definitely causing strain on other components. Glad I got it fixed when I did. Running the car with a failing alternator can definitely cause problems with other electrical parts like the starter motor you mentioned. When they did the alternator replacement, they also installed a new serpentine belt since everything was already apart. The whole electrical system is much more stable now, battery holds charge properly and all lights are bright as they should be. No engine misfire or other issues have shown up since the repair. If your starter is acting up, might be worth having it checked while its still an intermittent issue rather than waiting for complete failure. These electrical problems tend to cascade if left too long.

I finally got the alternator issue fixed last week after dealing with those power problems. The shop I found was actually great, really transparent about the whole process. They showed me the old alternator and how it was only outputting 11V, explaining why I was having all those car electronics issues. The full repair came to 780 Euro, which included the new alternator, serpentine belt, and labor. They had to remove quite a bit to access everything, but the mechanic walked me through what they were doing. The car won't start problems are completely gone now, starts up instantly every time. The battery warning light disappeared right after the fix, and the headlights are properly bright again. No more voltage drop issues either. Really glad I got it sorted before any other components could get damaged. The whole electrical system feels much more stable now. For anyone else dealing with similar symptoms, definitely worth getting it checked out early. Running with a bad alternator can cause bigger problems down the line.