Rough Virtus Engine + Check Light = Faulty Sensor Alert

Had similar sensor fault symptoms on a 2015 Polo TSI. The rough running during acceleration was identical to your description. Auto electronics testing revealed a faulty water sensor connection, not the sensor itself. The main issue was corrosion in the wiring harness connector that feeds data to the engine management system. The sensor testing showed intermittent readings which caused the engine to run rich at higher RPMs. A proper diagnosis involves checking both the sensor and its wiring, the connector pins often get damaged from engine bay heat and moisture over time. The fix required cleaning the connector housing and replacing the damaged pins. After repair, the check engine light cleared and the rough running completely resolved. This was not a serious repair but required specific diagnostic equipment to properly identify the root cause. Worth having a qualified technician do a complete circuit check rather than just replacing parts. Water sensor issues can mimic various other problems like fuel mixture or ignition faults. Getting accurate diagnostics first saves both time and unnecessary parts replacement.

Thanks for sharing that experience. Had similar problems with my 2017 VW. The car diagnostics also pointed to water sensor issues, but in my case the sensor itself was defective. The malfunction indicator kept coming on out of nowhere until I got it fixed. The mechanic isolated the problem using specialized sensor testing equipment. Wanted to ask, do you remember roughly what the repair cost? Also curious if the issue stayed resolved or if you had any other sensor related problems since then?

Since getting the water sensor malfunction fixed at the shop, I have not experienced any further electrical fault issues. The repair bill came to 95€ which covered diagnosing and fixing the faulty cable connection to the sensor. This was much cheaper than replacing the entire sensor unit. The auto electronics specialist confirmed the original diagnosis was spot on, the connection problems were causing erratic readings. The car sensor system has worked flawlessly for the past 18 months with no recurring malfunction indicator lights or rough running symptoms. I recommend keeping the repair invoice, as sensor connection issues can sometimes be related to a wider wiring harness problem. But in my case, the targeted fix of just the connector proved to be the right solution.

I finally got my car fixed after taking it back to a different mechanic shop. They did a thorough sensor testing process and found that my water sensor had completely failed, not just the wiring like in some cases. The replacement part and labor came to 280€ total. The repair process took about 2 hours since they had to remove some components to access the faulty sensor. The malfunction indicator cleared right after they installed the new unit and the rough acceleration issue disappeared completely. Been driving for 3 weeks now without any sensor fault warnings or engine problems. Really glad I got a second opinion instead of trying unusual fixes. The proper diagnostics equipment they used made all the difference in pinpointing the actual sensor issue rather than guessing.