Golf 1.9 tdi 2006 - P2100 P2102 fault codes

Hi, I have a VW Golf 1.9 tdi 2006 (UK).
A few days ago my turbo broke down and just had it replaced. However when I picked up the car from the garage they told me two fault codes appear:
P2100:Throttle Actuator Control Motor Circuit/Open
P2102:Throttle Actuator Control Motor Circuit Low

The mechanic suggested that the part needed (inlet manifold flap motor?) costs around 200quid so he suggested I drive it for a few days and if it does not go away, go back to replace it. He reckons that because the turbo failed, oil has gone into the flap hence the fault code.

Any ideas what that is and if it might have been caused by the turbo failure? also is it safe to drive or it might break down on me again?

Thanks in advance! I've already paid a fortune for the turbo so any help will be much appreciated!