Customer of mine has had this problem with his Ducato since he bought it three years ago. It's got the 2.2 Transit engine fitted to it. It's been back to Fiat 8 times with this fault code, all they seem to do is to erase the code and then within a few days it's back on.
I went out to it today, removed half the front end to get good clear access to the front of the engine. I removed the EGR pipe, valve/actuator, inlet manifold and cleaned out the pressure sensor on the intake pipe just where it joins the intake manifold. This was caked in soot/sludge and couldn't of been reading anything.
Also caked was the inlet and EGR metal feed pipe which runs from the Intake to the EGR valve. I reset the fault code and took it for a drive, it seemed a lot more responsive than it had been and drove lovely and smooth which it hadn't been previously. I covered about ten miles in it without a problem, rescanned it when i returned and all was good. He jumps in it a few hours later and the light jumps on straight away!
Anyone come across this fault code on these or a transit before being caused by another issue? I could only enter the system on OBD2 as it didn't go in on any of the Fiat or Ford software, this meaning I couldn't activate the valve itself the check operation.