Seat Mii Engine Error

That sounds familiar. I had a similar issue with my old Renault Megane. Engine light, reduced power, the whole shebang. Was there any work done on the timing belt recently? That can sometimes throw things off. Is the reference value error consistently appearing?

No work has been done on the timing belt recently. Why do you ask about that specifically? And what exactly does throw things off mean in this context?

The timing belt connects the crankshaft and camshaft, ensuring they rotate in sync. If it's worn or installed incorrectly, it can affect engine synchronization and cause that reference value error. But if no work has been done on it, a faulty crankshaft sensor is more likely. With those symptoms, I wouldn't risk driving it too much. Have you considered getting it checked by a professional?

The workshop confirmed the crankshaft sensor was faulty. They replaced it, and the engine synchronization is normal again. The engine light is off, and the car runs perfectly. Total cost was 340€.