Audi A6 Electrical Issues: Failing Alternator Warning Signs

I had a very similar issue with my 1999 Audi A4 2.0. As someone with some basic car maintenance experience, I initially thought it was just a dead battery, but it turned out to be more complex. The symptoms matched yours exactly, low battery voltage, struggling starts, and dimming lights. After monitoring the charging system, my workshop found the battery was heavily discharged and had internal damage from multiple deep discharge cycles. The complete diagnosis revealed: Battery voltage below 12V at idle, Loose battery terminals adding to the problem, Battery unable to hold proper charge The fix included: New battery installation, Cleaning and securing battery terminals, Full charging system test to verify alternator function Total cost was 290 Euro including parts and labor. The car has been running perfectly since then, with no more electrical issues. Before suggesting specific solutions for your A6, could you share: Current battery age, Voltage readings if you have them, Whether you notice issues more during short or long trips, If you have any aftermarket electrical accessories installed This information would help determine if your case matches what I experienced or points to a different issue.

Thanks for sharing your diagnostic results. Since my last service at 135622 KM, I did get a voltage meter reading from the battery, only 11.8V with the engine running, which confirms a charging system problem. The workshop quoted 450 Euro for a new alternator including the voltage regulator replacement. Based on my symptoms and your input about testing the charging system, I will follow through with the repair since all signs point to a failing alternator. Appreciate you mentioning the loose terminals check, will have them inspect those connection points while they do the alternator swap.

Glad I could help confirm your alternator issue diagnosis. Your 11.8V reading is definitely a red flag, a properly functioning charging system should show around 13.5-14.4V while running. After my battery replacement, I made it a habit to monitor battery voltage regularly. The voltage meter shows consistent 14V readings now, which is exactly where it should be. Looking back, I wish I had caught the alternator problem earlier before it damaged my original battery. The 450 Euro quote for your A6 alternator replacement sounds reasonable considering parts and labor. When they do the work, make sure they: Test the new alternator output after installation, Check all charging system connections, Verify battery health to ensure it hasnt been damaged My A4 has gone 40000 KM since fixing these electrical problems without any charging system issues. Let us know how the repair works out, it would be helpful for others facing similar symptoms.

Thanks for sharing the details about your A4 experience. The voltage meter reading of 11.8V while running definitely confirms my suspicions about the charging system issues. A healthy alternator and voltage regulator should maintain around 14V, so this really points to alternator failure. The price quote of 450 Euro for the alternator replacement seems fair based on current market rates. My battery is actually only 18 months old, so hopefully catching this alternator problem now will prevent any permanent battery damage from voltage drops. Will have them perform a full system check during the repair, including the battery terminals and all electrical connections. Based on both your experience and my symptoms, addressing this now should prevent more extensive electrical system failures down the road. Planned to schedule the repair next week. The consistent voltage drops during cold starts are getting worse, so better to fix it before being stranded somewhere. Will monitor the charging system voltage after the repair to ensure its maintaining proper levels.