I've been getting the OBD2 error code p3800 intermittently and I can't for the life of me find out what it is. Does anyone know?

Possibly relates to P0638 which pops up at similar times, relating to the throttle actuator control.

The car runs perfectly and I've driven 600 miles on it today towing a trailer without complaint, so I'm even more confused!

Car is an '04 Fabia Comfort 1.4L 16V

Any help would be greatly appreciated.

Thanks!

I never found out what the P3800 was, but cleaning the throttle body seems to have stopped it appearing. When I opened it it was completely gunked up and the valve had limited movement, so seems like a likely suspect. I was also getting temperature sensor errors so I'll be replacing that as well. Fingers crossed those offerings appease the Skoda gods...