Seat Exeo Diesel Gearbox Issues

Whoa, that sounds rough! Gearbox slipping and grinding noises are never good signs. Have you checked the basics, like the transmission fluid level and condition? Also, is the error code related to a specific sensor in the gear shift mechanism, or does it point directly to the control unit? Knowing the exact code would help a lot.

Fluid levels seem ok, although it's difficult to tell for sure. The error code relates to the control unit itself, saying something about 'implausible signal'. Is it possible that a faulty shift knob or the electronic display is causing the problem, or is the control unit the most likely culprit here?

An 'implausible signal' code pointing to the control unit combined with those symptoms definitely sounds like a bad control unit, unfortunately. It's possible a sensor problem or dodgy wiring could feed bad data to the unit, but it's less common. Since you're getting shifting issues and noises, I'd say the control unit is the prime suspect. I'm afraid a trip to a decent workshop is the way to go to confirm and get it sorted. Good luck!

Thanks for the confirmation. I took it to a shop, and they confirmed it was a faulty control unit. Cost me around 1000€ to get it sorted, but at least it's working properly now. Cheers!