Seat Leon Diesel Engine Trouble

I have a Seat Leon as well, though I'm not sure what year. I recall encountering a similar issue some time ago with the malfunction indicator illuminating and rough engine running. Have you performed any car diagnostics, and did you get a specific error code related to the water sensor? It may be an electrical fault affecting the sensor's readings. I suggest that you check the sensor and its wiring.

Thanks for the quick reply! Yes, I did a car diagnostics and it showed an error related to the water sensor. You mentioned an electrical fault - could you be more specific about what I should be looking for when checking the wiring? Any particular areas that are prone to issues?

That sounds very similar to what I experienced. In my case, the electrical fault was due to a corroded connector at the water sensor itself. The mechanics explained that this is a common issue. If the error code specifically points to the sensor and you've checked the wiring as much as you can, I'd recommend taking it to a workshop. They'll be able to properly diagnose and repair the electrical fault, or replace the sensor if necessary.

I took your advice and went to the workshop. They found a defective plug connection at the water sensor, just as you suspected. 95€ later and the Leon is running smoothly again. Thanks a lot for your help!