P0299 and p2261 trouble codes
 

Hello, I have a 2008 HHR SS 5 speed. gsm1 with K&N filter. Recently purchased it at an auto auction. At first I drove it around and noticed I wasn’t getting past 5lbs boost and figured it was running on some kind “Limp Mode” because the dic shows a Service ESC and airbag light. Plugged in the scanner and nothing. Check all the tubing for any cracks or leaks that would cause the low boost. Everything seems to be clamped and tight. Drove it around again and in 3rd gear got to around 4500 rpm and finally got a code. P0299 underboost and a pending P2261. Not sure we’re to start first to diagnose the issue. Maybe the BPV is stuck open. On idle the gauge says the vacuum is between 18-20 so that seems normal. Any help is appreciated.

Welcome - mmm WHISKEY!!!! Gotta try 40 Creek from Alberta if you can

Check out this thread for a p2261 error someone else encountered - https://www.chevyhhr.net/forums/ss-s...61-code-59833/

It is sort of strange; P0299 means underboost and P2261 means the bypass valve is stuck open.

Here is my guess: the charge air bypass valve vacuum tank has a malfunction. Or, the typical Stage 1 problem with the lower TMAP banging on the AC because the installer didn't modify the TMAP mount. Or, the crimp connections from the upgrade have corroded.

https://cimg2.ibsrv.net/gimg/www.che...6ff84552a1.png
https://cimg3.ibsrv.net/gimg/www.che...73bd22fc73.png

Welcome to the site, read causes, and possible cures

https://www.obd-codes.com/P0299

yes it is strange, actually this morning i got up to about 8lbs which it has never done. i will add though that the car wasnt moved or used in 6 months sitting in the auction parking lot. maybe the BVP is stuck because of non use. i will open it up today and see.

I think it opens with vacuum so a cracked vac line could do it. the 2 are related.

Just for kicks and giggles look at the wires and connector that are connected to the TMAP sensors to see if they are crimped or not.

i will have a look at them tomorrow. It definitely does not have the plug and play. Now when I accelerate and I get those three or 4 pounds of boost I do hear it blow off but not like a normal SS does, kinda sounds weaker.

Ok so I checked the diaphragm of the BPV and it looks good. Checked the wastegate actuator and i was not able to move the rod. So I added some WD to the lever and it moves now but is very stiff. I have to use my whole arm strength to even move it a bit. So I called it quits for the day. Then it hit me. The vacuum lines coming off the solenoid that is attached attached to the intake manifold were routed wrong. The one coming from the charge pipe was going into the intake manifold nipple. The one on the top of the solenoid pointed towards the windshield was coming from the vacuum tank. The one on the left side of the solenoid was going to the BPV (which is ok) and the bottom hose was going into the vacuum tank. So in actually the BPV was never getting vacuum. Would this be a reason for my issue? I feel this would cause overboost and not underboost. I have yet to put everything back the way it should be, but will be making those adjustments later today.

Here is the tube diagram, if you need it.
https://cimg8.ibsrv.net/gimg/www.che...0dcf3cd4ea.png

The picture below shows the vacuum hose routing and direction of vacuum pull.
Yellow: goes to and from the canister under the manifold.
Blue : is the hose to the lower charge pipe(nipple next to the lower Tmap sensor )
Red : is the hose to the bypass valve on the turbo.


https://cimg9.ibsrv.net/gimg/www.che...f6200d31e1.jpg

Service ESC Traction Control off
 

2008 HHR SS GSM1 5 Speed Manual. Would a Service ESC, traction control off showing on the dic cause my SS to be in some kind of Low Power Mode? Its not showing Reduced Power on the dash but car won’t go past 5lbs of boost. Checked for leaks and everything seems to be fine. I got the car off an auction so I’m not sure if was driving fine before the front end hit. So far have replaced intercooler, rack and pinion and clock spring. Not getting and codes or CEL. So hoping it’s in a low power mode of some kind and not a failing turbo. Also, how stiff should the actuator rod be because it takes my whole arm strength to even move it. Checked all the solenoids and are working fine. Thanks

Did you check the GMTU WIRING connections And the TMAP connector that should have been turned around but usually is not?

Serve ESC and Traction control usually comes from a pending code or some performance related fault. Why do you need ESC if you can't go fast?

Why start a new thread ?
It's most likely related somehow to the issues you talked about in your previous thread. You had codes pending in that one but never followed up there.
Best to keep it all in one place (thread)

merged

No more codes after rerouting the vacuum line coming from the charge pipe. I deleted the vacuum tank as well and still climbs up to about 4-5 psi and falls to 0. Will try performing a boost leak check later this week.

Pending codes don't set the CEL.

I don't think you can delete the vacuum tank and have it work correctly. There is a reason GM put the tank there to have a reserve supply. The system calls for vacuum at times it's under boost or not "pulling" a vacuum. Without the tank, it has no vacuum to pull from.

Look at the TMAP down next to the AC compressor Are the wires aimed at the compressor? If so, vibration makes it bang and fail.

Yes it is are pointed towards the ac. I will check the cables and o-ring tomorrow.

Correct, you can't delete the vacuum tank and have everything work correctly.

See post #3.

I will take some pictures of the lower sensor soon and post them here.

i see, is there a way I can test the tank to see if it still good? When I got the car, all those vacuum lines coming up from the solenoid on the intake manifold were plugged into the wrong spots.

Here is the entire TSB; to see the pix open the .pdf.

Attachment 47623