Codes are P2261, p0236. I took into the dealer today because it was missing and they said it had these two codes and to bring in next week. Well driving home it got alot worse, its severely under powered and the check engine light it on all the time.

Anybody know these?

 

P2261
Turbocharger Bypass Valve Stuck Closed

Diagnostic Aids

The bypass valve vacuum tank contains an internal check valve to prevent the tank from being pressurized during boost conditions. A leaking check valve will result in insufficient vacuum to open the turbocharger bypass valve after a quick throttle closing, causing abnormal pulsations and unusual noise.

P0236
Turbocharger Boost System Performance

Diagnostic Aids
• The intake air pressure sensor signal circuit is pulled high in the ECM. With the sensor disconnected, at ignition ON, a normal voltage measurement of the signal circuit with a DMM is 5.60 volts.
• The CAC is connected to the turbocharger and to the throttle body by flexible duct work that requires the use of special high torque fastening clamps. These clamps cannot be substituted. In order to prevent any type of air leak when servicing the ductwork, the tightening specifications and proper positioning of the clamps is critical, and must be strictly adhered to.
• Use a solution of dish soap and water in a spray bottle to pinpoint any air leaks.
• The BARO sensor is integrated within the ECM, and it has a port on the housing that allows it to sense the ambient pressure. Any restriction at this opening may hinder the operation of the BARO sensor.
Reference Information

 

well i took i had it towed to the dealer and they looked it over and couldn't figure out what was the deal. So they cleared the codes and sent me on my way. they said if it does it agian i should turn car off and back on. I am really starting to get pissed about the whole situation. Any ideas on what could be the problem/problems and how to fix them or duplicate for the dealer. That whole must duplicate thing is so stupid, pretty much my car had to be broke down for them to fix it.

 

Had P2261

Quick Shifts At Redline, should make it come on again

Had it three times...

First Time - Getting on the highway 2nd-3rd shift at redline caused it to come on
Not a serious.. issue so I just cleared it

Second Time - 1st - 2nd redline, took it to dealer this time they checked out said they couldn't find anything wrong/ or replicate the problem. like you.. but they did clean the valve or something..

Third time - 2nd-3rd again, had recently moved so went to the dealership by my new house... told them everything that happend.. the guy took it out called me back an hour later saying.. yea it seems like it's vacuum tank.. you can pick your car up I order one for you.

Went back two days later got it installed in I think 1hr...

1st-2nd-3rd redline leaving no problems

Just found this
https://www.cobaltss.net/forums/problems-service-maintenance-69/pi-lnf-intermittent-dtc-p2261-184458/
... I geuss a few people have had this problem since mine happened in apr 09

 

lol why did u tow it, just drive it there nicely, if ur scared just ask on here and im sure ull get an answer in a few minutes. plus there is a code thread on the top of lnf section so u can look to see if its bad.

 

I was on my way back from the dealer to show them what was up but of course didn't do anything, i was about a mile away from home and something went wrong, pulled out in 1st, nice and easy like a normal everyday person and it lost power and check engine light came on. Went for second hardly any power, it wasn't building boost. I didn't know what was wrong with it so i got it towed, warranty covered it. Today i was cruising on the highway around 60 and it kept cutting out. You could hear the slight whistle like you were letting of throttle but i wasn't. I even put it in cruise control on it did it a couple of times in cruise control. Im just going to keep driving it until it gets worse or something breaks. Im just puzzled at whats wrong. I do have stage 1 installed. And i did put ngk3787's in and thats when i noticed the problem so i removed them after the first incident and replaced the 3787's with the stock plugs

 

Well i was driving today and the car has been slightly hesitating every so often but on my way home from some errands it decide to give problems all the time, cel is on all the time and i had on-star check it. What do you know, bypass valve one of the codes before that the dealer said was and electrical issue and said the could get to duplicate. I'm getting really frustrated with this problem and the dealership.

 

did you not read my post above?

Get them to change the tank!

 

I would atleast bypass the vacuum tank and make sure thats not it .

 

Last night i need to run out and get a few things so i took my car. To my surprise when i started my car there was no cel on anymore. It didnt come on either while driving but its was still missing etc on the highway. It seems to be the worst once the car is fully warmed and its warm outside, yesterday was a bit colder then it has been. Anyways why did the cel not appear i thought the only way to clear them is disconnect bat or have them cleared from a scanner