RS6 Battery Issues: Multiple Electrical Problems Emerge

I had almost the exact same symptoms with my 2016 RS7, and it turned out to be more than just a discharged battery issue. Having some experience with electrical problems, I first thought basic battery charging would fix it. After multiple attempts at charging the battery, the problems persisted, error messages, hard starts, and system warnings. The workshop diagnosed a faulty battery sensor, which was causing incorrect readings and leading to battery drain issues. The battery sensor wasnt properly communicating the charging status to the cars computer. The repair involved: Full diagnostic scan, Battery sensor replacement, Battery terminals cleaning and testing, System reset and calibration Total cost was 315 Euro, which included parts and labor. The fix completely resolved all electrical issues, and the car has been running perfectly since. For your RS6, could you share: How old is the current battery? Are you seeing any specific error codes? Does the battery drain happen even when the car sits unused? Have you noticed any pattern with the electrical issues? This information would help determine if youre facing the same battery sensor failure or if its potentially a different electrical system problem.

Last service done at 17382 KM, and Im experiencing identical issues. The vehicle battery has been seriously acting up lately, despite regular maintenance. The error messages and diagnostic codes you mentioned match exactly what Im seeing. After checking the battery terminals myself, they seemed clean but the voltage reading was quite low at 11.2V. A battery failure like this seems premature for a 2018 model, but the car has been giving clear warning signs, dimming lights, slow cranking, and system errors that come and go. Just wondering, did your repair also include any alternator testing? My discharged battery symptoms persist even after longer drives, which makes me suspect the charging system might not be working properly.

Thanks for the follow-up details. The 11.2V reading is definitely concerning, its well below the 12.6V we should see in a healthy vehicle battery. When my RS7 had these issues, the workshop actually did test the alternator as part of their diagnostic process. The alternator tested fine, but they found the battery sensor was feeding incorrect data to the charging system. This caused the alternator to not charge properly, leading to the persistent discharged battery state. The key symptom that matches your case is the battery not recovering after longer drives. In my case, even a 1-hour drive wasnt enough to properly charge the battery. Once the sensor was replaced, the electrical system started working as intended. One difference I noticed, my battery voltage was reading 11.8V, slightly higher than yours. With your 11.2V reading, you might be dealing with both a faulty sensor and a weakened battery. The continuous improper charging likely damaged the battery cells. Would suggest: Get the alternator output tested, Have the battery load tested, Check battery sensor signals, Verify charging system voltage during operation The electrical system in these cars is quite sensitive, and one failing component can trigger a chain of issues. Best to have it properly diagnosed before the battery failure leads to more problems.

I appreciate all the detailed feedback about the battery sensor and alternator testing. The 11.2V reading on my battery definitely has me worried, and it makes sense that a faulty sensor could be preventing proper charging even during longer drives. This weekend I checked my service records, the battery is actually original from 2018, which likely explains part of the electrical system problems. Given the battery drain symptoms and the age, Im going to book it in for a full diagnostic. The battery failure is probably inevitable at this point anyway. The workshop quote I got was 290 Euro for complete testing of the charging system, battery sensor replacement, and a new battery if needed. After hearing about your successful repair, this seems like a reasonable approach to fix these electrical issues. Will schedule the work for next week and hopefully solve all these error messages and starting problems in one go. Good to know the sensor replacement fixed it completely in your case, gives me confidence its not a bigger electrical problem lurking somewhere else in the system.