VW Suran Engine Issue Linked to Faulty Moisture Sensor

As someone with some car repair experience, I had a very similar issue with my 2011 VW Fox. The moisture sensor fault code initially confused my diagnostic scan too, but the real problem turned out to be a damaged wiring connector near the sensor. The car diagnostics revealed that water had gotten into the plug connection, causing corrosion and intermittent signal issues. The workshop found this after testing the moisture sensor and its surrounding auto electronics thoroughly. The sensor itself was actually fine. The fix was relatively straightforward, they cleaned the connector, replaced the damaged wiring section, and applied special sealant to prevent future moisture issues. Total cost was 95€ for parts and labor. The check engine light disappeared and the engine has run smoothly since then. To help more specifically with your case, could you share: Have you noticed the issue more during wet weather? Are there any other warning lights besides the check engine light? Does the engine run rough at specific RPMs or all the time? Have you had any recent work done near the sensor area? The water sensor systems are pretty similar across these VW models, so knowing these details would help determine if your issue matches what I experienced.

Last service was 1000km ago at the dealership. I checked the repair history and found the moisture sensor was actually replaced during that service as part of routine maintenance. After that, the malfunction indicator started appearing intermittently. The engine runs especially rough during cold starts and the car sensor issue seems worse in humid conditions. I noticed the rough running mostly at idle and low RPMs. No other warning lights have appeared on the dashboard. I think might be onto something with the wiring connector suggestion. The timing lines up since these auto electronics problems started shortly after that service visit. Going to have the shop check the sensor connections and wiring harness first before replacing any more parts.

Thanks for those extra details, the timing of your issues starting after the dealer service really does point toward a connection problem, just like I experienced with my VW Fox. The similarity in symptoms is striking, especially the rough running during cold starts and in humid conditions. After my car sensor repair, I learned these VW moisture sensors are quite reliable, but their wiring connections can be finicky if not properly sealed during installation. The dealership might have missed resealing the connector properly during the routine replacement. Based on your description and my experience, I would specifically have them check: The connector seating and sealing at the new sensor, Any pinched or stressed wires near the recent work area, The ground connection which often gets disturbed during sensor replacement The car diagnostics should show intermittent signal patterns if the wiring is the issue, similar to what my mechanic found. Since your malfunction indicator started right after the service, get them to check their work under warranty, you might save the 95€ I had to spend on my repair.

Thanks for the input. After reading through the responses, I contacted the dealership about checking their recent sensor installation work. You were right, they found the moisture sensor connector wasnt properly sealed during the maintenance service. The service manager admitted their technician missed a step in the installation procedure. They fixed the wiring connection and properly sealed the sensor assembly under warranty. No cost to me since it was their error. The engine runs perfectly now, no more rough idle or check engine lights. The car sensor readings are all normal according to their diagnostic scan. Really glad I asked here before spending money on unnecessary parts. Sometimes the simplest explanation, a poorly sealed connector, is the right one. Lesson learned: even when a moisture sensor gets replaced, the installation and proper sealing are just as important as the part itself. Going to keep an eye on the repair quality at future services.