I have a 08 turbo that will not biuld any boost. I have checked for leaks and didnt find any. When its cold it will go to 7psi and the the drop off to nothing once it warms up. I tell you one thing these car sux with out the turbo. Feels like im driving a dam go-cart. Any info will help. One other thing i tried is disconnecting the battery and that didnt work.

 

may be in valet mode?
i dont even know if those have it but it's just a guess

 

There are bullitons out for the wastegate seloniod. That could be the problem. There is also a buliton for a bolt that is on the radiator suport rubbing on the charge pipe under the left side of the car (looking at it from the front). Could also be it

 

i also have the same problem.but i ve checked all the aftermaket pipeing and nothing.i have apill mod,maybe thinking its that

 

Have you looked at the intercooler for leaks. There is a bulleting out on intercoolers deforming and leaking. Check to see that the intercooler passages are parallel.

 

Oh really, I don't recall seeing this one and I move ever bulletin posted here to our provincial Cobalt forums so there's a central reference...

 

Probalby not your problem, but you can check the adjustment nut on the actuator rod (on the turbo).

Mine came loose when the car was new and it would not build any boost at all.