Seat Leon Hybrid check engine warning light

A defective knock sensor will certainly cause those symptoms. The warning light is a clear indicator. Given the mileage, it is plausible that the cable or plug connection is faulty. However, before replacing the knock sensor, have you checked the wiring and connections to the sensor? Is there any visible damage or corrosion?

Thank you for your quick reply! I did a quick visual inspection of the wiring, but I didn't see any obvious damage. Is there a specific method for testing the wiring and connections that you would recommend? Or would it be better to simply take it to an auto repair shop?

Given that you've already observed those symptoms, and particularly if you're uncertain about electrical testing, perhaps the wisest course of action is to take it to a trusted auto repair shop. They can accurately diagnose the wiring and confirm whether the knock sensor itself is indeed the problem. It is better to be safe than sorry.

Fantastic advice! I took your suggestion and visited my local auto repair shop. It turned out to be a defective knock sensor cable, just as you suspected. The auto repair set me back 95€ including labor, but now the warning light is off, and the engine seems to be running smoothly once again. I am also hoping that fuel efficiency will improve. Thank you so much for your help!