Seat Ateca rough running and exhaust smell

Sounds familiar. I had a similar issue with my old Renault Megane. Check engine light, the whole shebang. In my case, it was also a faulty sensor messing with the exhaust readings. Does it smell strongly of exhaust, like unburnt fuel?

Yeah, the exhaust smell is pretty strong, especially when I first start the car. Did your Renault also have a rough idle, like it wanted to stall? Also, did you ever have to top up DEF fluid or deal with the particulate filter?

The rough idle and strong smell definitely ring a bell. It's like the engine is choking, right? I never had to mess with DEF fluid on that car, but the symptoms are similar to what I experienced. If I were you I would go to a workshop

Just wanted to close the loop. Took it to the workshop, and you were spot on. Turned out the lambda sensor was indeed defective. They replaced it, and the check engine light is gone, the rough running is fixed and no more exhaust smell. Cost me 375€, but at least it's sorted. Thanks for the help!