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klausberger1

RS6 Electrical Gremlins: Beyond a Battery Problem

Recently my RS6 (2016) has been acting up with multiple electrical problems that seem related to power supply issues. The car struggles to start, lights are dim and flicker, and various systems fail intermittently. My diagnostic scan showed an undervoltage error code. While the battery terminal connections look clean, Im suspecting a deeper electrical problem or voltage regulator issue. Has anyone encountered similar symptoms? Looking specifically for tips on troubleshooting steps and repair experiences. Would be great to hear what the actual problem was in your case and how the repair shop resolved it. Did a simple battery replacement fix it or was there more to it? My main concern is to identify if this is a battery health issue or something more complex in the electrical system before heading to a workshop.

4 comment(s)

juliusfox1

Having faced similar symptoms with my RS7 (2018), I can share my experience as someone with moderate car repair knowledge. The electrical problems you describe match my situation exactly, dim lights, starting problems, and unusual system failures. Initially thought cleaning the battery terminals would fix it, but the alternator issue persisted. After a thorough check at the workshop, they found that while the battery was heavily discharged, the root cause was a faulty voltage regulator. The alternator wasnt properly charging the battery, leading to the low voltage situation. The repair involved: 1. Full electrical system diagnostic 2. Battery load testing 3. Alternator output measurement 4. Voltage regulator replacement 5. New battery installation Total cost was 290 Euro and it completely resolved all electrical problems. The car has been running perfectly since then. Before suggesting specific solutions, could you share: Current battery age? Any recent electrical modifications? Does the battery warning light come on while driving? Have you noticed any unusual alternator noise? This information would help determine if youre facing the same underlying electrical problem I encountered.

klausberger1 (Author)

Thanks for the detailed information. Just had my 150000 km service last month and wanted to share my resolution. After getting multiple diagnostic scans, it turned out my voltage regulator was indeed failing. The alternator issue caused a constant voltage drop which drained the battery. The workshop found the original voltage regulator had worn contacts, preventing proper charging. They also detected minor wiring corrosion near the alternator connector. After replacing both parts and installing a new battery, all electrical problems disappeared. Total repair cost was 470 Euro and the car runs perfectly now. The voltage reading at idle is steady at 14.2V, exactly where it should be.

juliusfox1

Thanks for sharing your repair experience. Its interesting that we both had similar voltage regulator failures in our RS models. The steady 14.2V reading you got after the fix matches what I saw in my case, its the optimal charging system output we should expect. The corrosion you found at the alternator connector is a crucial detail I missed in my initial troubleshooting. These connection points are often overlooked when diagnosing power supply problems. My mechanic now includes checking these spots as standard practice for any low voltage complaints. Your repair cost was higher than mine due to the additional wiring work, but still reasonable considering the comprehensive fix. These charging system repairs tend to solve multiple issues at once, the stable power supply eliminates those unusual electrical gremlins that are so frustrating to diagnose. For anyone else reading with similar symptoms: the battery terminal connections might look fine on the surface, but its worth checking the entire charging circuit, including the alternator connections, before replacing parts.

klausberger1 (Author)

Just had a follow-up after 3 months and wanted to share the long-term results. The power supply has remained rock solid since the voltage regulator replacement. No more battery voltage issues or electrical glitches whatsoever. For anyone tracking voltage readings, mine stays consistently between 13.8V-14.2V while running, which confirms the charging system is working as designed. The battery holds a perfect charge even after sitting unused for a week. The workshop mentioned they often see similar low voltage problems that people mistake for just a weak battery. Getting that full diagnostic revealed the actual voltage regulator failure before it could damage other components. The investment in fixing both the regulator and wiring has definitely paid off. No more flickering lights, struggling starts, or system failures. Makes me wish I had investigated the charging system issues sooner instead of just assuming it was battery-related.

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