Audi S5 Alternator Failure Signs, Repair Shop Needed

Had the exact same alternator issue on my 2012 Audi S4 last winter. The symptoms match perfectly, weak starts, dimming lights, and charging system warnings are classic signs of alternator failure. The alternator replacement was necessary because the voltage regulator had failed, causing unstable power delivery to the car electronics. The starter motor was getting inconsistent power, explaining the sluggish engine behavior. When my alternator was tested, it was only producing 11.2V instead of the required 13.5-14.5V. The repair involved removing several components to access the alternator, as its tucked away in these engines. They also checked the battery condition and drive belt since these can be related issues. This is definitely a serious repair that requires specific knowledge of Audi electrical systems. A failing alternator can leave you stranded if not addressed promptly. The job typically takes 4-5 hours due to the complex removal process and testing required. Make sure the shop performs a full charging system diagnostic before starting work. They should test both the alternator output and battery condition to confirm the root cause.

Thanks for sharing your experience. That was really useful since I have the exact same symptoms in my S5. I am planning to get it checked this week since the car won't start reliably anymore and the engine misfire is getting worse. Do you remember roughly how much you paid for the alternator replacement including parts? Also wondering if you had any related issues pop up afterward, especially with the serpentine belt or other electrical components?

Had the alternator issue fixed last week and it was definitely the right call. The complete repair including parts came to 960 Euro. The generator was completely faulty, causing all those starting problems and electrical glitches. After replacing the defective generator, the charging system is working perfectly again. No more engine misfires or starting problems. The mechanic also inspected the serpentine belt during the repair and found it in good condition, so no additional work was needed there. No related issues have appeared since the fix. The starter motor now gets proper power, and all electrical systems are functioning normally. The dashboard warning lights have completely disappeared, which confirms it was definitely the alternator causing all those problems. The repair cost was worth it considering how critical the alternator is for keeping the car running. When they tested the old unit, it was only putting out about 11V, way below what the car needs to operate properly. Getting it fixed before other components got damaged was definitely the right move.

Thanks for the advice. Wanted to give a quick update on my S5 situation. Finally got it fixed yesterday and the mechanic confirmed it was indeed the alternator causing all those problems. The total repair came to 890 Euro, which included a new OEM alternator and labor. The repair process went smoothly. They found the charging system was barely outputting 11V, explaining why the battery kept going low. They also spotted some wear on the serpentine belt while they were in there, so I had that replaced too for good measure. The difference is night and day. No more engine misfire, all electronics working perfectly, and the car starts right up every time. The dashboard warning lights are completely gone. Pretty relieved I got it sorted before any other components were damaged. Was definitely worth getting it fixed at a shop that specializes in these engines. They did a thorough job testing everything in the charging system to make sure there weren't any other underlying issues.