You could first try a basic setting for the intake manifold motor in vcds but in all honesty I think you'll be needing to renew the motor.
Prerequisites:
Ignition ON
Engine OFF
System voltage at least 11.0 V.
[Select]
[01 - Engine]
[Basic Settings - 04]
Group 142
[Go!]
Activate the Basic Setting.
[ON/OFF/Next]
Wait until Field 4 shows "ADP. O.K.".
[Done, Go Back]
[Close Controller, Go Back - 06]
Switch Ignition OFF for at least 60 seconds.