VW Touareg Water Sensor Issues Causing Engine Problems

I had a similar sensor fault on my 2010 VW Tiguan with a 2.0 TSI engine (moderate experience with VW repairs here). The symptoms matched yours exactly, rough running engine and malfunction indicator light. The diagnostic scan pointed to moisture sensor issues, but the actual problem was simpler. After inspection, the workshop found a damaged cable connection going to the sensor unit. They discovered corrosion had built up where the wiring harness connects to the sensor. The fix involved cleaning the connector pins and replacing a section of the wiring harness. Total cost was 95€ including diagnostic work. The repair resolved both the rough running and the check engine light. Before suggesting more specific advice, could you share: Which engine variant is in your Touareg? Are there any other warning lights active? Does the rough running happen more when the engine is cold or warm? Have you noticed any changes in fuel consumption? This information would help determine if your issue matches what I experienced with the sensor testing and repair on my Tiguan. Tip: Keep all diagnostic codes recorded before any repairs. This helps track if the fix actually resolved all active faults in the system.

Last service was completed at 124000km. The rough running occurs mainly when the engine is warm. Fuel consumption increased by about 2l/100km in the past month. The auto electronics seem to compensate by adjusting the fuel mixture, which might explain the higher consumption. I am noticing the check engine light comes on after driving for about 15 minutes. No other warning lights are active. The engine variant is the 3.6 FSI. My local parts supplier quoted 280€ for a new moisture sensor unit, but I want to confirm this is actually needed before making the investment. The malfunction indicator started appearing intermittently about 2 weeks ago before becoming constant. I have saved photos of all sensor fault codes from the diagnostic scan for reference.

The symptoms you describe with your 3.6 FSI sound different from what I experienced with my sensor issue, despite some similar indicators. My Tiguan showed problems immediately on cold starts, while yours develops after warming up. The 2l/100km fuel consumption increase is noteworthy. In my case, the faulty wiring connection caused erratic sensor readings, but didnt significantly impact fuel usage. Your car sensor system appears to be getting incorrect readings only at operating temperature, suggesting a different root cause. Based on the electrical fault patterns you describe, particularly the timing of when the malfunction indicator appears, I would investigate the temperature-dependent connections first. The moisture sensor might not be the primary issue here. When my car had the wiring problem, the auto electronics showed consistent errors regardless of engine temperature. Your situation sounds more like a component that fails when it heats up. The error memory logs you saved will be valuable for tracking this pattern. Consider having the entire sensor circuit tested at different temperatures before replacing the moisture sensor unit. In my repair experience, temperature-related electrical faults often trace back to damaged insulation or cracked connectors that expand with heat. Could you share what specific fault codes were stored? This would help compare if they match the codes from my sensor repair case.

I have reviewed both sensors fault codes and temperature-related patterns mentioned. Those error codes from my diagnostic scan are P0195 and P0106. The rough running and increased fuel consumption match what several others experienced, but the timing of the check engine light activation seems unique to my situation. I agree that checking the wiring connections and temperature-dependent components makes sense before replacing the moisture sensor. The 280€ investment in a new sensor unit would be wasted if the root cause lies elsewhere in the auto electronics system. The workshop should be able to perform sensor testing at different operating temperatures to properly diagnose the electrical fault. Based on the responses, I will request they specifically: Check wiring harness conditions and connections, Test sensor circuits at various temperatures, Verify if the current moisture sensor readings are accurate, Inspect for any signs of connector corrosion I will keep the full diagnostic scan records to compare before and after any repairs. This systematic approach should help avoid unnecessary parts replacement and identify the true source of the sensor fault. Thank you for sharing your repair experiences. The feedback has helped create a more focused troubleshooting plan.