Audi S6 Engine Warning: Water Sensor Issue Alert

Had a similar sensor issue with my 2019 Audi S4, which shares many electrical components with the S6. I have some experience working on basic car maintenance, but auto electronics definitely required professional help. The malfunction indicator light was persistent and engine performance was affected, just like your case. After sensor testing at my regular workshop, they discovered a faulty cable connection to one of the engine management sensors. The wire insulation had worn through, causing intermittent connection issues and triggering the system warnings. The repair involved replacing the damaged wiring harness and properly securing all sensor connections. Total cost was 95 Euro for parts and labor, which seems reasonable given the diagnostic work needed to pinpoint the exact source of the car diagnostics error codes. To better assist with your specific case, could you share: The exact error codes from your diagnostic scan, Whether the rough running is constant or intermittent, If the issue started suddenly or developed gradually, Any recent work done on the engine This information would help determine if your sensor issue matches what I experienced or points to a different underlying problem.

Thanks for sharing your experience. After seeing I have a similar issue, I took my S6 (182786 KM) for a professional diagnosis yesterday. The mechanic found multiple moisture sensor faults in the ECU logs. The rough running seems connected to a failing water sensor in the intake manifold, causing incorrect fuel mixture readings. Getting it fixed next week. The shop quoted 450 Euro for parts and labor, which includes replacing both the faulty sensor and some corroded wiring. Hopefully this resolves the engine performance issues and clears those persistent error codes showing up in the car diagnostics. Would still appreciate any feedback from other S6 owners who might have dealt with similar sensor related problems.

Thanks for the update on your S6. Your diagnosis matches what I eventually discovered with my S4, moisture-related sensor faults can be tricky to diagnose without proper equipment. The 450 Euro quote seems in line with what I ultimately paid, as my initial 95 Euro repair was just the start. After the first fix, I ended up needing additional work when the electrical fault symptoms returned. The complete repair on my car also included replacing corroded wiring and multiple sensors. The car sensor issues in the intake manifold area are a known weak point in these engines, especially at higher mileages. After my repair, the rough engine running completely resolved and the malfunction indicator hasnt returned in over 8 months. One tip from my experience: make sure they thoroughly check all nearby connections while they have the intake manifold accessible. In my case, they found additional water sensor corrosion that wasnt obvious during the initial inspection. Addressing everything at once saved me from repeat visits. Keep us updated on how the repair goes. These sensor-related issues can be frustrating, but once properly fixed, the car should run like new again.

Thanks for the detailed follow-up. The issue ended up being more extensive than my mechanic first thought. After getting the car back from service today, they found additional auto electronics problems while doing the repair. The moisture sensor replacement uncovered severe corrosion affecting multiple car sensor connections near the intake manifold. Final repair bill came to 720 Euro, quite a bit more than the initial quote of 450 Euro. They had to replace two additional sensors and a larger section of the wiring harness. While the cost stings, the engine now runs perfectly smooth and all car diagnostics are finally clear. No more malfunction lights or error codes showing up. For anyone dealing with similar sensor fault issues in their S6, definitely get it checked early. What seems like a single failing sensor can indicate wider electrical problems that worsen over time. Will update this thread if any issues return, but for now the problem appears fully resolved.