GM Repair Problems? Ask GM Repair Expert Now.
Your mechanic needs to check if the VNG vanes are jammed up in the turbo, from soot.
I would also see if the learn procedure can be carried out.
That is usually what the final diagnosis is, to replace the whole unit.
Most of the time, the VNG vanes are jammed up, and no boost occurs.
Many mechanics will just replace the whole lot.
Glad you have it sorted now.