Understand, brother, I was in that exact same place less than 2 months ago. It started boosting to 20 PSI and then P0234 with no turbo (2-3PSI), not really full limp mode. But when you're trying to pass a semi truck, and all of a sudden no turbo? Not good.

In less than 2 weeks, it was slamming to 25 PSI in the blink of an eye (didn't even have to floor it anymore!), accompanied by a screech. I was trying to be careful, but old habits... I had to fix this. I replaced the solenoid, problem solved.

Unfortunately, now I have low compression in cylinder #4. It may just be coked up valves, but it could be something serious. I hope you can get yours fixed soon.

I'm not saying that the solenoid/ elec. connector is the only possible cause, But in my research, it was much more often the cause than anything else. If the elec. connector is falling apart, there's a post in that css link I provided for that too. If you haven't read those threads yet, there's good information. And after seeing some of the attitudes over at css, you'll appreciate the people here even more.

 

So went through the piping no leaks... Don't know how to check the wastegate spring but also another thing is that when I hold the boost steady at 14-15psi for a few seconds it will still put into limp mode, someone told me the throttle body could be cracked... I'd rather not replace the turbo of that's not the problem also, still trying to narrow down.... Advise please !!! No vacuum leaks or IC piping leaks and now that I had the forge bov valve trying to hold any kind of boost for a little bit of time it releases pressure....

 

Interesting, now 14-15 psi triggers your overboost? I wouldn't have expected that. I wonder if it's because of elevation?

Yes, 3 seconds of continuous overboost or 50 seconds cumulative overboost will pretty much shut down the turbo.

Did you see the information I gave you in post #13?

 

Forge BPV or BOV ? BPV would be an easy bolt on swap for the stock one. Now a BOV unit requires a relocation and tune I believe.

 

it happened to me last night. 2009 - owned since new - had the gm stage 1 done 6 yrs ago. so gm has a tsb that states the wastegate rod is out of adjustment - - I don't believe that can be the case - I bought the car new & no one ever touched the turbo, so , how can the rod be out of adjustment on it's own? wouldn't it be out of adjustment from day 1? is it true the solenoid is not available seperatly - you have to replace the turbo just to get the solenoid?

 

Others have posted a replacement solenoid is available in the aftermarket, the adjustment can be considered out if the solenoid is faulty, so the computer can't read specific parameters


http://www.full-race.com/store/efr-t...ent-kit-1.html

 

I thought I saw a listing on either AutoZone or Advance the other day as I was racing through a drill down.

 

I believe it's the wastegate solenoid you can't get separately. At least I can't find one. The boost control solenoid on the intake manifold is available. I haven't figured out a way to tell which is the issue with my over boost which then triggers no boost and a low mass flow pending code. It happens rarely so its hard to troubleshoot. The maps and wiring are fine.

 

OB's post and link points to the WG solenoid. GM alternative is to buy a complete Turbo

 

The solenoid on the turbo is the boost control solenoid, controls the wastegate.

The solenoid on the intake manifold is the bypass solenoid, controls the bypass valve. Yes, it is still available from GM.
SOLENOID | Genuine GM | 12633411
Ecotec LNF Bypass Valve Solenoid 12633411

If it were a code for underboost, we would be looking at the bypass solenoid as a possible culprit.