P0244 21 fault and air entering engine fouled up

[Mrus24]

I have a Citroen relay euro 5 with electronic turbo actuator.I have a p0244 fault code and I’m trying to trace the fault.I’m leaning towards it needing a new actuator or sticking turbo vanes but also when I do a test which checks for air entering the engine it is coming back as fouled.Does this mean the actuator is sticking or another problem.Any advise much appreciated thanks Mark.