Audi S1 Moisture Sensor Triggers Rough Running Issues

I had a similar sensor fault on my 2019 Audi S3. The malfunction indicator kept lighting up, combined with rough idle and occasional stuttering during acceleration. The diagnostics pointed to a moisture sensor issue, which turned out to be more complex than initially thought. The root cause was a corroded wiring harness connector near the sensor, creating an electrical fault that triggered false readings. What appeared as a simple sensor issue actually required replacing the entire wiring section and connector assembly. This was a serious repair as the faulty signals were affecting multiple engine management systems. Car diagnostics revealed that moisture had slowly damaged the connection over time, common in these engine configurations. The repair involved removing several components to access the wiring, cleaning the connection points, and installing new sealed connectors to prevent future corrosion. For your S1, considering the similar engine architecture, I suggest having the wiring thoroughly checked before simply replacing the sensor. A complete diagnostic scan should reveal if there are any additional electrical faults in the circuit. This type of issue typically worsens over time if left unaddressed.

Thanks for sharing your experience with the S3. It really helps to hear how you resolved a similar water sensor problem. The wiring harness issue you mentioned sounds exactly like what might be happening with my S1. The malfunction indicator symptoms match up perfectly. Did you remember roughly how much the full repair cost? Also, has everything been running smoothly since the fix, or have you noticed any other sensor testing issues come up?

Just got back from dealing with my sensor issue and wanted to update you. The repair was much simpler than my S3 case, turned out to be just a faulty plug connection to the moisture sensor. The auto electronics specialist found it pretty quickly during sensor testing. Total cost was 95 Euro for fixing the cable connection, which was way less than I initially paid for my own repair. The malfunction indicator hasn't come back on since, and the engine is running perfectly smooth now. No more rough idle or stuttering. When they did the full sensor testing, they confirmed no other electrical issues in the circuit, which was a relief. These moisture sensor problems can be tricky to diagnose, but once fixed properly, they usually stay fixed. My car has been trouble-free for several months now. The key was finding someone who really understood the sensor issue and took time to check the wiring connections before jumping to replace parts. Definitely worth getting it sorted rather than letting it get worse.

Thanks everyone for the helpful input. I finally got the car checked out at a different shop that specializes in auto electronics. The mechanic found the exact same wiring harness issue mentioned, a corroded connector was causing the moisture sensor malfunction. The repair took about 2 hours. They cleaned all connection points, replaced the damaged wiring section, and installed new weatherproof connectors. Total cost was 280 Euro including parts and labor. Much better than the 800 Euro quote I got from the previous shop who wanted to replace multiple sensors. The car runs perfectly now, no more check engine light or rough running. The electrical fault is completely resolved. Really glad I got a second opinion from a shop that actually took time to properly diagnose the sensor issue rather than just throwing parts at it. Looking back, I probably should have addressed the problem sooner, but at least it's sorted now. Thanks again for steering me in the right direction with this repair.