if we Connected to MES the result is: P0639-12 Throttle Actuator(2) Short Circuit to V+ Throttle Actuator Control Range Performance (Bank2)
with this information and the information of Icar: there ist short Connection to V+ (5V) in the wires to the PWM Controlled Throttle Actuator, so you have to Check your Wiring Loom, Connection at Throttle Actuator
Ducato P0638 Throttle Valve Command
P0639 Throttle Actuator Control Range/Performance (Bank 2)
With above the throttle body connections look a sensible place to start. The older models were sensitive to this issue with water getting from the skuttle. With this model i have seen one that resolved the problems with a new throttle body (different code, cant remember which but cant get at my data now.) Previous P0401 and new EGR Valve. When i looked down it it was quite clean and moved correctly but 3 months later new problems. Start with connectors and looking for corrossion and continuity / 5v 0v in right plces.
The only other throttle body ive looked at was a vw cayc engine in a skoda absolutely coked up at 90,000 miles. There was a yank youtuber suggesting it was a routine job at 60,000 on all vws in his shop.