P0234 code
 

I got this code the other day when I pulled out to pass another car. Question is, how safe is it to drive with this code even for a few days on short trips until I can get it to my dealer to investigate further?

Give this a read for some insight to your code

http://www.obd-codes.com/p0234

From what I read as long as engine temps dob't rise and boost is within limits it's safe to make a short trip, under 25 miles round trip, if necessary?

That what I would limit my drive to, and have a look at the suggested problem areas!
Like your MAP sensor and hoses

I don't have time to read through all of the 27 threads that "p0234" in the search box returned. If I remember correctly, it's a relatively easy to fix problem.

Here's one thread Okie....

https://www.chevyhhr.net/forums/ss-s...age-1-a-46427/

Short hops with an Overboost Code shouldn't do any real harm, just keep you foot out of it until you've found the fault and it's corrected.

Experiencing the same. 2009 SS 5 speed, no mods other than TTR motor and trans mounts. 86,000 mi. I've had it for about 1 1/2 years. Was going up the grade yesterday, on it in 3rd gear, shifted into 4th and... no turbo! What? No CEL, maybe 2-3 PSI boost.

Stopped at AutoZone to pull codes (which they say they can't do), headed to O'reilly's and everything seemed fine, good boost. Ended up at JiffyLube to read code P0234.

I put it up on ramps today to see what I could see. Everything looks near pristine except for an oily, sticky residue collected on the bottom of the plastic tube that connects the airbox to the turbo.

I've been through many threads here, a few people have reported this same residue, but no one has said what may be causing it or if it is normal. It does not appear to be leaking or dripping from anything above. The inside of the tube is clean at the airbox.

Took it out on the freeway to see how much boost. It spiked between 20-25 PSI. (And now the CEL is on) I saw a TSB on here that points to the wastegate. The vast majority of related threads are for vehicles with a tune.

I'll have to check the vacuum line connections. Everything looks so good, I don't expect to find a fix with that, but I'll check tomorrow. I may need a new bypass valve?

Pulled the codes again yesterday, still only p0234. Removed and inspected the bypass valve, the spring and diaphragm both look great. The MAF sensor looks spotless.

The oil is definitely coming from inside the turbo. Perhaps an internal crack allowing oil to leak out? Could internal cracks be causing the overboost also?

I tried to manually move the wastegate pushrod. It took a lot of force to move it. I have no frame of reference as to how much force it should take. I have doubts that a line with a spring clamp could hold en

Is the turbo lubricated by the engine oil, or does it have its own oil, of which some of it is now gone?

Turbo is lubricated by engine oil. It does take some effort to manually open the waste gate, more than likely it's the waste gate solenoid. I would say that some of the oil you are seeing in the inlet of the turbo is coming from 1 of the 2 PCV valve systems on these engines.

If I'm looking at the PCV valve, it's plugged into the inlet hose, just downstream from the MAF sensor, in the bend of the hose from horizontal to vertical. It has what seems to be a check valve, with an arrow and the word "flow". The arrow is pointing from the inlet hose to the engine.

IF this is a check valve, and installed correctly, and functioning properly, there should be no oil in the inlet hose, right?

EDIT: PS there is no residue in the vertical part of the inlet hose, only a buildup in the bottom, where it clamps to the turbo.