Seat Cordoba Start Stop Problem

Sounds like a battery issue to me. I had a similar problem with my Cordoba some time ago. The eco mode stopped working, and the engine would sometimes cut out at traffic lights even without the start-stop active. Did you check the battery voltage? Also, does the engine start without problems, or does the starter motor sound weak?

I haven't checked the voltage, but the engine always starts fine, though maybe the starter motor sounds a bit slower than usual. Could a slightly weak battery really disable the whole start-stop system? I thought it would only affect the engine start.

Yes, a weak battery can definitely disable the start-stop system. The car's computer is very sensitive to voltage drops. The start-stop system puts a lot of strain on the battery, and if it's not in top condition, the system will shut down to protect it. Given that the engine still starts, it might not be completely dead, but definitely weak. I would suggest visiting a workshop to get it checked properly. They have the right tools to test the battery under load. Don't risk damaging your starter motor further.

Thanks for your help! I went to a workshop and they confirmed it was the battery. Replaced it for 290€ and the start-stop system is working again. Hopefully, the starter motor didn't suffer too much from this battery issue.