Transit Connect How to test if the EGR valve is faulty

[Sbob27]

Hi
Have a 2008 Connect 1.8 TDI. The engine management fault light came on last week and I read the fault code as P141A. This suggests either faulty wiring or faulty EGR valve but the engine seems to run OK.
So before investigating the wiring or buying a replacement EGR valve does anyone know what electrical conditions present on the EGR wiring in normal and/or fault conditions.
In other words, what changes to the wiring voltage level does the EGR valve make when in fault mode? I'm thinking perhaps +12V on one of the output wires or perhaps 0V or even open circuit.
Is there a way of testing the EGR valve??

Appreciate your help guys.

Dave (electrician but, sadly, not a vehicle electrician)