Hi could you explain why did you divert the whole circuit to the turbo?
All is very simple. In a collector the gage pressure\vacuum is established. When you release a pedal, egr Is opened on 100 % and is closed air valve as on 100 %. Pressure falls to certain parameter. If simply to establish a plate that parameter it will be too small - result check vsc. If submit air from turbo we can't to receive vacuum in a collector!
I have egr closed for over 5 days and there are not any errors on VSC. For sure if you remove that circuite and just close the valve you will also see that VSC won't trow error. But it is a matter of personal choise I think. Thank you for the clarification and have a great time driving :)
Rgds