04 WRX, 19k mi, stock minus silencer, EGT in manifold, boost gauge

Over the weekend I got an unexplained CEL. Then I noticed my turbo had been making a very faint high pitched noise for about a day or so and then went intermittent and then stopped completely. I'm worried it s'd the bed. I've visually checked the vacuum lines to no avail. Could it be the boost solenoid? how can i check the lines more thoroughly? i should have a MBC coming tomorrow in the mail that I was going to use w/ a UTEC (not installed yet). EGT at the manifold is below norm as to be expected w/ no boost.

Am i correct in thinking that installing an MBC will help eliminate the solenoid as being the problem? Could it really be the turbo, i figured when they went it was a lot more eventful... Dealer is booked for a while here and I wanna try myself b4 bringing it in. The motor seems to be running ok otherwise so could it be a clogged cat? It worked fine, and then not at all, not a gradual loss of boost.

Any help greatly appreciated!

 

so, i guess everyone else is as stumped as i am. tried a MBC and still no boost. the actuator control arm is connected as far as i can see too. still haven't found any vacuum leaks. it's starting to look more and more like it is the turbo.

 

...why not just take off the MBC and bring it to the dealer? Still within warrenty and you don't have any major mods to worry about them deying your claim.



Edit: Sorry, just saw your dealer is booked up...I'd wait though, get it fixed free by the pros...

 

Did you get the code read to see what actually caused the CEL? That should have been your first step. You can still do that, go to a nearby Autozone and they will scan it for free. Get the code(s) in Pxxxx format and then search for them here and elsewhere online. You should find info on how to troubleshoot that specific code.
As for the turbo, it's unusual to have a failure at that low mileage on a minimally modified car. Normally a disconnected actuator is the cause of sudden and total boost loss, but if you have checked for that the next step is to remove either the inlet hose or downpipe and see if the shaft spins. If the turbo is ok it will spin smoothly and with little resistance. If it is seized or stiff then your turbo is indeed shot.