turboss09

Alright well i have been having the same problem over the past three months off and on. Its similar to the thread "whats causing my wacked fuel trims". The car sometimes will not boost over 5psi other times it will be fine. Also driving along at middle throttle just maintaining current speed the car will miss and hesitate but yet again thats off and on. I had it to the dealership for this problem. The first time they said it didn't duplicate for them, but did have a dtc but no cel. Second time there the cel was on and it did duplicate after they drove it for over 70 miles, they replaced a sensor. Well problem still not fixed, took it up to the dealer and dropped it off. They call and say they have to order sensor in but its gonna be a couple of days and i should come pick my car up. I went to get my car theres another 50 miles on it from when i dropped it off so that made me mad. I figured the part would be in after a week but i called Friday and there saying they wont have the part till july 5th at the earliest. My first year of owning the car runs out june 26 and i know there not going to fix the problem, will i still be able to lemon the car? Should i wait until after they put new part on and it acts up or start now. I don't want to get rid of my car but i want something i can drive anywhere anytime and not worry about it. And it can't be good driving it underpowered like it is when its acting up. Sorry about the long post lol. Any input is much appreciated.

yel-low

Well I think you should wait and see what happens also I thought you could only claim lemon if it is a safety issue or internal engine problem what code is it do you know

blk06cbltss

iTrader: (1)

damn bro sorry to hear about the ss

turboss09

current code is P2261. Yea it does suck, i cant drive it like i want to. And what whats makes it worst is the only mod is stage1, i wanted to keep my warranty no ?'s asked and im having problems lol figures. I do have a hanh catted dp waiting to go on hopefully after this mess gets clean up if it ever does get fixed once and for all

turb@baltmotorsports

if not, im intested in the exhaust!

G Speed

I had that p2261 3 times before it was fixed...
1st got dealer to clear it "maybe it would go away on it's on"
2nd they cleaned the valve "dealership by my work"
3rd they replaced the whole tank "moved, and took it to the dealership by my house"

After that the car has been great, and no more p2261

turboss09

Thanks for info g speed, ill mention it to them. They keep saying its a map sensor part # 55206797. Ill tried telling them that its something with the bypass valve itself or something other then map sensor but the swear its the problem. I told them that some problem is causing the map sensor to get a false reading which inturn causes a dtc/cel to come on but what do i know lol. I just want my car fixed and back to normal.

Forgot to ask g speed to have the part number for the tank the replaced so i can give it to my dealer, they are confused enough already and trying to explain that to them would be nest to impossible. Lol every time i take it in they say thats the cobalt with the stage 2 upgrade correct. I just roll my eyes and tell them no they only have stage 1 for lnf!!!

G Speed

lol, stage 2 lnf kit is badass lol... i'm not saying that my problem is the same as yours.. I did have the same code, but I only got that code when I would do highrpm, quick shifts... and no not NLS... after they replaced the tank... Quickshifts, NLS I have no problems so I hope this helps

COMPLAINT: CHECK AND REPORT ON CUSTOMER CONCERN WITH SES LIGHT ON ERROR CODE READS P2261
CAUSE: TURBO CHARGER VAC TANK LEAK
CORRECTION: J5860 1.3 REPLACED VAC TANK

Parts
Qty - 1
FP-Number - 12626029
Description - TANK 033420

Good luck

ecot3c inside

iTrader: (11)

swap ecu's and see what happens, maybe the ecu gave up? and if the problem stays the same, check all the other stuff cps, maf, tps, bov? seems logical.

rukkee

iTrader: (3)

Service Information
Home Publications Number Search New Bulletins Bulletin Search Feedback Help
2009 Chevrolet Cobalt | Cobalt, G5 (VIN A) Service Manual | Document ID: 2324723
#PIP4669A: Intermittent DTC P2261 Setting - (Aug 10, 2009)

Subject: Intermittent DTC P2261 Setting

Models: 2008-2010 Chevrolet Cobalt SS
2008-2010 Chevrolet HHR SS

This PI was superseded to update model years. Please discard PIP4669.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

A technician may find DTC P2261: Turbocharger Bypass Valve Stuck Closed set with no problem found. It may be intermittent in nature or they may find the dtc will set after a hard acceleration, usually in third gear. DTC P2261 is a type B dtc and will not set on the first drive cycle the dtc sets, therefore multiple test drives should be performed to confirm repair.
Recommendation/Instructions:

SI diagnostics for this DTC states that the ECM compares the measured MAF reading to the modeled MAF and has detected a series of pulsations in the induction system that exceed a calibrated threshold. A snapshot of "Induction Data" will show the fault, however the tech may need to compare the snapshot data to another vehicle if they are unfamiliar with the readings. They should note a fluctuation and or a difference in the desired versus requested boost level. When diagnosing this dtc pay close attention to Circuit/System testing step #1. This step has you inspecting for any vacuum leaks, damage, restrictions, improper routing or connecting of the vacuum hoses on the charge air bypass valve solenoid, the charge air bypass valve, and the charge air bypass valve vacuum tank.

We have found leaking vacuum tanks causing this dtc. When testing the vacuum tank, care must be used or the results may not be valid. The vacuum tank has an integral check valve not noted in SI. To check the Vacuum Tank operation, disconnect the hose that runs from the tank to the Bypass Valve Solenoid at the solenoid and apply vacuum to the tank. The tank should be able to maintain vacuum with no decay. Note: If you remove the vacuum hose from the intake manifold and plug it and the decay stops the check valve is leaking, if the decay continues the tank itself is leaking.

Note: Front wheel drive platforms using the 2.0 Liter RPO (LNF) incorporate a charge air bypass valve supplemental vacuum tank. The purpose of the tank is to provide an instant source of vacuum to the bypass valve via the bypass solenoid (when it is commanded open by the ECM). This results in less pressure buildup under closed throttle conditions, thereby reducing compressor noise, surge and spool time.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.


WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
Š 2010 General Motors. All rights reserved.

Permafried-

What's brutal is I remembered the TSB you posted above and I'd be willing to bet not a single technician at the OP's dealership has even looked these up. Even worse, some of what they recommend sound to be what they did for g speed which resolved his issue.

OP, print this off, take the number in and tell them to look it up. I found that my dealer will check the system, but don't seem to know what they're looking for. When I take it in on paper first they question how the hell I got it, then they typically just go along with it if the description is the same as the issue.

I keep sayin all these TSBs rukkee has posted should be stickied, but now they're so buried it's too late

G Speed

Yes, about a month after they replaced the vacuum tank, that TSB came out

turboss09

i did one better, i called customer service and told them whats going on and that i wanted to speak with "zone manager" for my area. I gave all the info problems its having that TSB above that seemed to have been overlooked by the dealer. So the wheels are in motion, lol im just curious as to how fast the dealer gets a phone call from the higher ups. I can understand there being problems with a car but when the keep happening like they are over and over something needs to be done and its gonna

80vetteL82

This is the SAME EXACT problem I was having with my GMS1 and Dejon SRI. I threw a MAF sensor code and a MAP sensor code. I went back to the stock airbox, but the problem persisted for a while. Since then it resolved on its own and has been fine......for now. But it was seriously the same issue....under partial throttle, just cruising, it would start to buck violently....then it would only boost 5psi. I had my car about a year and a half before this started though, and it was like 6mos after my GMS1 was installed.

rukkee

iTrader: (3)

I asked about a sticky for just TSB's but didn't get a response. I'm glad people get some use out of them. I would go back and get them all if Css.net would keep them together.

Technical

* #08-09-41-002F: Diagnostic Information for SIR System, Intermittent AIR BAG Indicator/Lamp Illuminated with DTC(s) B0012, B0013, B0015, B0016, B0019, B0020, B0022, B0023, B0026, B0033, B0040, B0042 or B0044 Set - (Jun 10, 2010)
* #10-08-44-003A: Buzz Noise During Call When Using Bluetooth (Replace Microphone) - (Jun 9, 2010)
* #07-06-04-019C: Intermittent Malfunction Indicator Lamp (MIL) Illuminated, DTC P2138 with Reduced Engine Power (Repair Instrument Panel (IP) to Body Harness Connector) - (Jun 2, 2010)
* #05-03-10-006D: Wheel Squeak (Install Wheel Cover Insulators) - (Jun 2, 2010)
* #06-07-30-004G: Various Concerns with Shifter and/or Ignition Key (Perform Repair as Outlined) - (May 27, 2010)
* #09-08-50-008B: Passenger Seat Wiring Harness Disconnected or Damaged, SIR/Airbag Indicator Light On, DTC B0081 71 Set (Reposition or Replace IOS Wiring Harness) - (May 3, 2010)
* #05-03-10-003F: Low Tire Pressure, Leaking Cast Aluminum Wheels (Repair with Adhesive Sealant) - (Apr 27, 2010)
* #08-03-10-006C: Tire Slowly Goes Flat, Tire Air Loss, Low Tire Pressure Warning Light Illuminated, Aluminum Wheel Bead Seat Corrosion (Clean and Resurface Wheel Bead Seat) - (Apr 27, 2010)
* #06-03-09-005D: Squawk/Squeak Type Noise from Rear Suspension While Driving Over Bumps at Low Speeds (Replace Rear Suspension Insulators) - (Apr 15, 2010)
* #09-01-37-002B: Front and Rear Passenger Floor Carpet Wet (Inspect White Plug in HVAC Evaporator Drain and Apply Sealer to Front of Dash Area) - (Mar 26, 2010)
* #09-02-35-005B: Ignition Key Difficult to Remove, Ignition Key Binds or Sticks in Cylinder (Replace Ignition Cylinder) - (Feb 4, 2010)
* #10-08-46-001: Radio Does Not Mute Enough When OnStar Turn-By-Turn Navigation Directions Are Announced (Increase Volume Setting or Request Soft Mute Feature Change Through OnStar Customer Service) - (Jan 27, 2010)
* #10-06-04-001: Intermittent MIL/Check Engine Light On, DTC P0442, P0446, P0451, P0452, P0453, P0454 or P0455 (Install Fuel Tank Pressure Sensor Cover) - (Jan 6, 2010)
* #09-08-46-004A: Generation 8 OnStar Modules Inoperative and Possible Battery Discharge Condition (Replace OnStar VCIM) - (Dec 17, 2009)
* #09-08-58-003: Wind Noise from Door Glass, B Pillar or Sunroof Area and/or Front Fender Rattle (Repair/Align Components) - (Dec 10, 2009)
* #09-06-01-014: Oil Leak by High Pressure Fuel Pump (Reseal Camshaft Cap) - (Dec 3, 2009)
* #09-06-03-004C: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules-Diagnosing and Repairing Fretting Corrosion - (Nov 24, 2009)
* #09-08-49-018: Instrument Panel (I/P) Outer Compartment Bin is Inoperative or Loose (Replace Steering Column Opening Filler Panel) - (Nov 20, 2009)
* #06-09-41-004J: Passenger Side Air Bag Door Not Flush with Dash Pad/Warped (Reposition Locking Tabs on Air Bag Panel or Replace Air Bag Door) - (Nov 6, 2009)
* #08-09-41-006D: SIR/Airbag Light Illuminated, DTC B0081 (Passenger Presence System (PPS) Code) Stored (Inspect PPS System Connectors) - (Nov 4, 2009)
* #06-08-111-004B: Information on Discoloration, Blistering, Peeling or Erosion of Various Exterior Emblems Including Chevy Bowtie (Bulletin Canceled) - (Sep 25, 2009)
* #09-05-25-003: Brake Pedal Spongy, Increased Pedal Travel, Increased Effort to Stop (Replace Brake Pressure Modulator Valve (BPMV) and Bleed Brake System) - (Sep 21, 2009)
* #09-08-48-006: Clear Stain or Film on Inside Perimeter of Windshield Glass (Clean/Polish Glass) - (Sep 18, 2009)
* #09-09-40-003: SIR/Airbag Light Illuminated, DTC B0081 and Passenger Presence System (PPS) Code 23 Stored (Replace Passenger Seat Belt Retractor and Re-Route Wire Harness) - (Aug 11, 2009)
* #07-08-46-002D: Audio Whine Noise from Radio Speakers When using OnStar (Install Noise Suppression Filter) - (Jul 29, 2009)
* #09-06-93-004: Intermittent MIL/Check Engine Light On, DTC P0299 or P0234 Set (Adjust Turbocharger Wastegate Actuator) - (Jul 21, 2009)
* #09-09-41-004: Instrument Panel Cluster (IPC) Air Bag Indicator Illuminated (Install Protective Material) - (Jun 23, 2009)
* #05-08-51-008C: Bumps or Rust Colored Spots in Paint Due to Rail or Iron Dust (Remove Rail Dust) - (Jun 22, 2009)
* #99-01-39-004C: Air Conditioning Odor (Install Evaporator Core Dryer Kit and Apply Cooling Coil Coating) - (Jun 12, 2009)
* #08-08-64-009A: Outside Rear View Mirror (OSRV) Difficult to Adjust, Will Not Move Through Full Range of Adjustment (Check for Proper Engagement of Mirror Body to Adjustment Tower) - (Jun 8, 2009)
* #09-08-64-020: Front Side Door Glass Loose in Channel, Wind Noise, Water Leak (Revise Window Regulator Mounting Hole) - (May 20, 2009)
* #03-06-04-030G: Various Driveability Symptoms Due to Clogged Fuel Injectors, MIL/SES DTCs P0171, P0172, P0174, P0300, P1174, P1175 (Clean Fuel Injectors and/or Perform Injector Test with AFIT CH-47976) - (Apr 22, 2009)
* #09-06-01-004: Clicking/Ticking Sound/Noise Heard from Rear of Engine (Install Sound Isolation Cover Over High Pressure Fuel Pump) - (Apr 1, 2009)
* #09-09-41-002: SIR/Airbag Light Illuminated, Passenger Presence System (PPS) DTCs 023, 024, 063, 064, 065 Set (Inspect PPS System Wiring and/or Connectors) - (Apr 1, 2009)
* #06-08-67-019B: Headliner Wet at Center Map Light/Sunroof Switch Area (Adjust Sunroof and Apply Lube) - (Mar 25, 2009)
* #09-08-48-002A: Marks/Stains on Windshield When Wet (Clean Windshield) - (Mar 19, 2009)
* #04-03-08-006D: Steering and Front Suspension Noise Concerns - Clunk, Thump, Rattle, Knocking, Pop, Shudder, Vibration (Diagnosis and Perform Necessary Repairs) - (Feb 24, 2009)
* #09-08-67-001: Sunroof Frame Tox Rivet Rattle (Install Flocking Tape) - (Jan 6, 2009)
* #08-08-44-032: Newest Generation of iPod and iPhone Will Not Connect to Radio, Device Not Authorized Message Displayed (Reprogram Radio) - (Dec 10, 2008)
* #06-08-50-005C: Seat Cushion Cover Loose (Secure J-Strip to Seat Frame With Hog Rings) - (Oct 1, 2008)
* #01-07-30-032E: Transmission Oil Leaking From Transmission Vent (Replace Transmission Case Cover (Channel Plate) Gasket) - (Sep 29, 2008)
* #08-06-01-017C: EI08224 - 2.0L LNF, 2.2L L61, 2.4L LE5 Engine Oil Leak (Repair Leak) - (Sep 22, 2008)

G Speed

Marks/Stains on Windshield When Wet (Clean Windshield)

LMFAO.. seriously

turboss09

Update: Gm called my house today and said the parted need for my vehicle has not been shipped. Later on that day i receive a phone call on my cell from the dealer saying the part came in and the car is ready to go, they tested in the heat were and having and no problems. Well i go and pick it up drive 20 min to home and stop and make an errand quick get back on highway BAM problem back. I'm so frustrated at this point not even funny any more.

Sevensix9

Hey brother I have gone through a very similar situation with my car, same issues and all, turns out they replaced my PVC valve and it all cleared up. Problem was it was stuck open and when the tank pressurised it caused the car to see odd readings. they could never duplicate it, but one time they did after going in and out the dealership for 4 months

-Alex

KnightSS/TC

Sorry to hear the bad news about your lnf, I would try to tuff it out. I have had a Trifecta tune for about 3500+ miles & not one single problem.

Permafried-

That's one thing I'll give GM Customer Service is they will try to help you out with your problem when the dealership can't figure it out. Without rukkee posting the TSBs I find dealers never pay attention to them and keep re-inventing the wheel so to speak. In I go with a printout in hand and say "Car is doing 'X', here do this"...no questions asked though they're not sure how I'm getting a hold of them .

I see the problem still isn't fixed from your other post, but oddly enough a friend of mine who recently put the GMS1 in had the exact same problem a couple weeks ago after the kit was installed. Stock no issues and would boost to ~15PSI consistently. After GMS1 was installed, it wouldn't boost over 5PSI and he threw a CEL (sorry I never asked for the code so it might be different ). Turned out he had a hole in the intercooler that had never been discovered and once this was replaced the issue was corrected and the car has been running great since.

FRQ FLYR

iTrader: (1)

I think I've officially joined the list as well.
GMS1/catted downpipe for approx. 8k or so. Couple weeks ago started getting the intermittent hesitation/bucking @ part throttle or when lifting(no cel's or problems boosting). Couple days ago tipped into it and boost stopped @ 5psi-next morning had a cel. Haven't had it scanned yet but I reset the ECM and it hasn't returned; going to the dealer in a few days.
My best guess is that the vaccum tank is trying to take a dump(I'll be taking the ^ bulletin !) however I haven't seen many folks with custom tunes chiming in(sensors?)
Wish me luck

turboss09

I called the dealer this morning and they said that the same code is coming up. They FINALLY believe that something else has to be causing this other then the sensors, small victory lol. Anyways they are having a gm service tech/engineer guy or w.e come out and look at the car to see if he can figure it out. We will see what happens, and ill keep posting updates.

Permafried-

Have him smoke test the system for a boost leak just in case they missed something

turboss09

bump, i got my car back from the dealer and after an engineer came out to look over the car the problem was determined to be caused by the stage 1 sensors being butt-connected when they should have been soldered. So far the car "knock on wood" has been good and has not acted up. I just don't see soldered/butt-connected wires being the much of a difference but maybe that truly was the problem. Anyways i thought i would update and share for others out there having the same/similar problem looking for answers to fix it. Im gonna give it atleast a week before i put my hanh dp on that has been sitting on my floor for 3 months now, just to be sage and make sure car is all good.

mongorat427

iTrader: (82)

I eliminated my tank last year and havnt had a problem since