Common Rail VNT Actuator for the Borg Warner Turbo.
P00AF Turbo Code
We're finding that code is commonly associated with one or more of these things
1) an old turbo that's getting worn out
2) weak actuator
3) vacuum system leaks/ issues
4) boost leaks
Very difficult to change with the turbo on the car, but do-able. Turbo install kit available <HERE>
Vacuum system should be gone through for leaks. Maybe just replace all vacuum hoses.
examine the charge pressure system carefully for boost leaks between the turbo and intake manifold.
VW dealers will just replace the whole turbo, but replacing the actuator typically does the trick.