T-Cross Engine Light + Rough Running: Water Sensor Alert

Had the exact same symptoms on a 2017 VW Polo TSI. The moisture sensor malfunction combined with rough running turned out to be a corroded connector at the water sensor housing. The electrical fault caused incorrect readings, making the engine run rich. The repair involved cleaning the sensor contacts and replacing the wiring harness connector. While inside, the mechanic performed sensor testing on the entire coolant monitoring system to rule out other issues. The original electrical fault was causing the ECU to receive wrong temperature data. This type of water sensor issue can quickly escalate if left unchecked. In my case, the faulty readings were affecting fuel mixture and ignition timing. The check engine light appeared because the ECU detected inconsistent signals from the temperature monitoring system. The proper fix requires testing both the sensor and its electrical connections. Sometimes cleaning the connector solves it, but often the entire sensor unit needs replacement to prevent future issues.

My T-Cross actually had very similar symptoms last summer. The malfunction indicator came on and the engine felt rough, especially when cold. Turned out the moisture sensor was sending incorrect signals, just like in your case. Getting the sensor fault fixed definitely solved the performance issues. Would be curious to know what repair costs you ended up with and if everything has been running smoothly since the fix? From my experience with VW sensor issues, they sometimes come back if not addressed properly the first time.

The repair turned out exactly as expected, 95€ to fix the faulty cable connection at the water sensor. The moisture sensor malfunction completely cleared up after the mechanic repaired the corroded wiring connector. The auto electronics have been working flawlessly since the fix six months ago. The service technician explained that these sensor fault issues often stem from water intrusion damaging the electrical connections over time. Having the entire connector assembly replaced rather than just cleaned was key to preventing the problem from returning. No check engine light or rough running since then. The engine temperature readings are now stable and the ECU receives accurate data from the sensor. Based on the diagnostic results, addressing the electrical fault at the connector was definitely the right call rather than replacing the entire sensor unit. Proper repairs of these sensor issues are critical, when moisture gets into these connectors it can cause ongoing electrical faults if not fixed correctly the first time.

Today I took my T-Cross to get checked after seeing your replies. The malfunction indicator was spot on, showing a faulty water sensor connection. My mechanic found corrosion in the wiring connector, just like your case. After testing the sensor and cleaning the connections, they recommended replacing the entire connector assembly to prevent future sensor issues. Total repair came to 110€ including parts and labor. The auto electronics diagnostic confirmed the sensor fault was causing the rough running. The engine now runs perfectly smooth and all temperature readings are normal. Really glad I got this fixed properly instead of trying temporary solutions. No more check engine light or performance problems. Thanks for helping me identify the likely cause, saved me from replacing parts unnecessarily.