Audi S5 Battery Sensor Issues Causing Start Problems

As a regular DIY car enthusiast with some hands-on experience, I had a very similar issue with my Audi S4 (2009). The symptoms matched exactly what you describe, weak starts and flickering lights pointed to issues with the battery system. The voltage sensor on my car was indeed faulty, causing incorrect readings and improper battery charge management. After proper diagnostics at a specialized workshop, they confirmed the battery sensor was defective and needed replacement. The entire repair including parts and labor came to 315 Euro. The fix resolved all issues, no more starting problems or dim lights. The battery maintenance system now works perfectly, monitoring voltage levels correctly. To provide more specific guidance for your case, could you share: Current battery age, Any warning lights on the dashboard, Whether you notice these issues more during specific weather conditions, If you have done any recent electrical modifications The low voltage problems you describe are common in this model range, but proper diagnosis is essential since similar symptoms can stem from different causes. Would recommend getting professional diagnostics done to confirm if the battery sensor is actually causing your issues before replacing parts.

At 44956 KM with my latest service done recently, I can confirm the battery sensor replacement fixed all starting issues completely. The repair cost was 320 Euro including installation and voltage sensor recalibration. The vehicle diagnostics revealed the old sensor was sending incorrect readings to the ECU. The low voltage problems disappeared immediately after the fix, and battery maintenance is now working as intended.

Thanks for the update on your S5 repair. Great to hear the battery sensor replacement resolved your issues too, just like it did on my S4. My repair cost was nearly identical at 315 Euro, showing these repairs are fairly consistent price-wise. The vehicle diagnostics definitely proved crucial in both our cases, confirming the faulty voltage sensor was the root cause. Since the fix, my battery maintenance system has been running flawlessly for over a year now, with no more cold start problems or electrical issues. For anyone else reading with similar symptoms: the battery sensor plays a vital role in proper charging system operation. When it fails, it often leads to these battery health issues despite having a good battery installed. Getting proper diagnostics is worth the initial cost to avoid replacing parts unnecessarily. Good to have this confirmed on another vehicle in the same model range. These battery management systems are quite sensitive but work great once properly calibrated.

The battery sensor replacement has completely resolved all starting issues on my Audi S5. After 44956 KM and getting a recent service, I can confirm the repair was worth the 320 Euro, which included installation and voltage sensor recalibration. The vehicle diagnostics were essential, showing the old sensor was sending incorrect readings to the ECU. Since the fix, my battery maintenance system is working perfectly. The car starts reliably even in cold weather, and the battery voltage stays consistent. The low voltage problems and dim lights are completely gone. The battery health monitoring now works as intended, making this repair a definite success. For other S5 owners facing similar issues, having proper diagnostics done first saved me from unnecessarily replacing other components. A faulty battery sensor can mimic various electrical problems, but professional testing can pinpoint the exact cause.