Seat Leon cruise control malfunction

Interesting. My Leon had very similar symptoms but in my instance the dashboard light illuminated too. First, have you checked the speed sensor? Sometimes a faulty speed sensor can cause the cruise control to disengage or not engage at all. It's a common issue. Also, is there any chance a blown fuse is the culprit? Cruise control systems often have their own dedicated fuse.

The speed sensor is working fine, as the speedometer reports the speed correctly. I have checked all fuses, but I will check them again. I haven't seen any dashboard light, could it be related although all other lights work perfectly?

Yes, a faulty connection can absolutely explain the lack of a dashboard light. The power might not be reaching the indicator, but the cruise control module itself is still failing. Although less likely given your model year, also consider the clock spring in the steering wheel or the steering wheel buttons themselves. My advice? Given the error code and your observations, it's best to let a workshop diagnose the specific cause and rectify the issue. It will save you a lot of time.

Thanks for the feedback. Took it to the shop, they found a defective connection on the cruise control module. 95€ and it's sorted.