Low turbo speed X15

[tree98]

Well, I followed the troubleshooting tree on quickserve and everything checked out ok so I replaced the speed sensor and cleared the codes. So far the codes haven't come back so I'm thinking that was it. Quickserve says that on rare occasions the turbo itself has been known to cause this code. Made me wonder how you could test the turbo? Or would you just have to replace it and hope for the best?