640d need help with no boost fault!!

[mariodix98]

Hello i have an 640d and i have some fault codes that says Boost pressure actuator VNT. The car has bad boost up to ca 2500rpm and after that it goes like crazy.
I think it’s the electronic wastegate on the small turbo. Do someone know what it can be?

The codes:
292200: boost pressure actuator (VNT): position sensor in the boost pressure actuator defective or undervoltage.

27B900: exhaust pressure upstream of the turbine, plausibility: difference between measured and calculated exhaust pressure to low.