[Hi again. Please Please can someone help . Got a turbo problem. T16 Engine runs ok but

no turbo pressure. There is a hose from what I think is waste gate diaphragm to a 3 way solenoid. From which a pipe goes to air filter and the other to a pipe underneath the throttle. If that makes sense?? Please can you tell me if this is correct and how does this solonoid work?
Could it cause loss of turbo pressure??. Thanks . Dave