Could be a boost tube blown off or leaking or hole in a boost tube or intercooler cracked.

Brian

 

Thanks Brian for those suggestions. There's nothing obviously detached or damaged based on a visual inspection, so we'll see what the techies find when I take it in later this week.

 

That sucks man, how many miles do you have on your truck now?

 

all these problems with the new truck ... did GM drop the ball on quality? Aren't they supposed to be "like a rock" - reliable?

 

No, they quit with the Like a Rock slogan with the LB7. Its Like a Dump now.

Not that I hate the LB7, but it has cost us tons of cash in repairs in the amount of time we have owned it.

 

Hey, what's with all the negative stuff ??? The truck is FANTASTIC. It tows like a demon, power and torque to spare, I love it !!!! I'm certainly not writing it off just because it has had a low boost error. Get real guys, and wait for the tech report after I've been to the dealership.

 

Hey Ted....these days i think there is a lack of QUALITY control, you me and the rest of pay alot lot of money for these trucks for something to go wrong

 

I'm actually very happy with the quality, if that means that the panels all line up nicely, and everything works the way it should - VERY different to the standard for North American vehicles 30 years ago. That having been said, a 2011 vehicle is extremely complex, so I'm actaully surprised that most of them have no problems whatsoever. Prior to the 2011, I owned a 2007.5 and a 2008 and neither had any significant issues, just minor warranty jobs. Same goes for this 2011. I don't want to jump to conclusions about the quality just yet. Maybe I'll change my mind after the Dealership visit, but I'll report back with the results.

 

I really love mine and I will also say the quality is much better than it was 10-20 years ago. But, as the old saying goes, "If it has tires and t-ts, your going to have problems with them sooner or later"

 

If it makes anyone feel better, the New Dodges and Fords are throwing just as many or more codes. These computers now tell us if something isn't perfect. In the old day's you didn't know something wasn't right until you heard a noise or lost power ect. So far these 11's are doing very well. there are a lot more of them on the road than we realize. There are some with 35,000 miles or more running around so far with no issues.

 

At about the eleven hundred mile mark our 2011 gave the same code. Called onstar as we were towing on the road. Took it to the dealer the next day and all was fine. I just got some shoulder shrugging at the dealer.

 

Did the dealer pull the code and do a snapshot? It could just be a gremlin, but they should at least get GM involved to solve the issue. I know it can be annoying.
I bet after John Kenedy get's a chance to play with these LML's he will figure out what's going on. GM would do well to hire him for tuning and tweaking the ECM's. He just seems to take thier stuff and make it better.

 

OK, just got back from the dealership. When I took the truck in I told them about the engine light coming on, that I had read code P0299, and I expressed concern about the average fuel consumption, which is higher than was the case with my LMM.

Told them that all of the GM sales promotions claimed that the LML would have BETTER mpg, not worse.

Didn't take them much more than half an hour to bring the truck back to me. They told me that GM is aware of this issue and is working on a solution. The tech service rep told me that the fuel consumption and low boost error code appear to be linked in some way.

Anyway, he said not to expect a fix until the first of the year, and he mentioned a PIP4849 which documents the issue.

SO, can anyone get hold of a copy of PIP4849 ???

 

Here you are Ted:

#PIP4849: Intermittent Turbocharger Engine Undeboost DTC P0299 - (Nov 10, 2010)

Subject: Intermittent Turbocharger Engine Underboost DTC P0299
Models: 2011 Chevrolet Silverado
2011 GMC Sierra
Equipped with the 6.6L Duramax Diesel RPO codes LGH or LML

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

Condition/Concern:

A dealer may encounter a customer concern of low power or the SES light coming on.

Basic diagnosis may reveal a Engine Underboost DTC P0299.

Recommendation/Instructions:

Complete the current SI diagnostic for any DTCs or symptoms found.

If diagnostics are inconclusive and the concern cannot be duplicated, do not attempt repairs.

GM engineering is aware of the concern and the intermittent P0299 is under investigation

This PI will be updated when new information becomes available

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.

 

I got a CEL and onstar said it was a turbo related code also. I am not sure if we are talking about the same one or not. Truck was low on power and ilding a little higher than normal (while smoking from under the hood, which was never fixed by dealer) This paired with the shitty hitch from B&W is really making me pissed off!!

 

I got the same code yesterday at 900 miles. It was a turbo power Boost problem that GM is aware of. They say they are working on the software that will fix the problem. I should have known there was a problem as my mileage went down prior to code coming up.

 

I just got the low boost code today also Onstar says it will come on if the boost is 7 lbs under normal, mine came on in the parking lot.

 

I had the same code again today. This is the third time and I find it curious it only happens when I am pulling the fifthwheel.

 

Is this CEL actually causing the truck to go into limp mode or is it just throwing a CEL light and nothing else?

Personally I would be surprised if the new trucks didnt have any glitches, that goes for ford, dodge, and gm.

 

Great I tow all the time and dont need this. For what ever reason mine went off in a parking lot. Since I cleared the code the dealer wont look at it until it throws another code. Do you notice a loss of power like the turbo is under boost? Mine just finished a regen the day before.

 

I had a P2565 code last week. Turbocharger boost control position sensor circuit high voltage. Truck was low on power and idling.
Took it to the dealer and traced the fault to the ECM.

Replaced the ECM.

Tomorrow I hook the RV up and see how she pulls.

 

Let us know how it goes first time in my life im hoping for a code so I can take it to the dealer.

 

The truck does NOT go into limp mode. In my case, the engine light went off again after 48 hrs, before I went to the dealership. Interestingly, and perhaps of some importance, I did not have the code until I was towing my fifth wheel. Anyway, it's not serious enough to cause any problems at this stage so I'm happy to wait for the fix.

 

My LML has been absolutely flawless, 7500 miles, and it has just handled everything I have thrown at it with ridiculous ease.

Awesome mileage, performance, and everything else.

I do not think it is possible to build a better truck, period.......

 

Just got the p0299 code yesterday. No limp mode. reset it thinking possibly that it was a fluke and it stayed out untill the same strecth of interstate where it came on before interestingly enough. To me it seems to be someting with sustatined boost. Im at 2200 miles. This is my 3rd issue with this truck. I love GM but if I wanted a $55,000 garage orniment I would have bought a powerstroke.....Starting to wonder if i should have......

 

X2
I traded in a perfectly fine 2007 LMM for a $51000 head ache
I rely on my truck 7 days a week to haul a livestock trailer which is how I afford to make the payments on it!! WTF

 

Hey Coltxxxxv,

What were the other two issues you have had?