Engine dies at 50%+ throttle

[90kpaperweight]

Brand new to the forum here. 2023 Yukon Denali with 3.0 Diesel. Engine completely dies when giving it more than half throttle and throws "Service Emision System See Owners Manual" and "175 mi Until 65 MPH Max Speed". Can reproduce it every single time we try. Started with power cutting in and out rapidly when accelerating, now the engine just dies. Left my wife stranded on the freeway.
The dealership has had it for over a month with still no diagnosis. They have a TAC case open with GMC but still nothing. They have replaced the cam shaft sensor to no avail. Other Googling I've done points to replacing the DEF tank and Sensor. I should mention that this thing has also been guzzling DEF/ 10K miles and has drank over 8 gallons of DEF.
Started the process of a rebuy with GMC but have not heard back. The UAW strike will likely make that more difficult as time passes.
Any ideas or similar threads I may have missed? Thanks in advance!

2023 Yukon Denali
10,000 miles

 

[B-train]

I'd wager there's something wrong in the emissions system. Back pressure issues, sensor issue, plugged for some reason, manufactured wrong, etc. Maybe an injector that is dumping fuel.

 

[BrokerThis]

I wouldn't say that you are guzzling DEF... many people on the forum seem to be averaging 1000-1400 miles per DEF Gal.

As I haven't experienced this first hand, I can't give any exact advise, but my gut says something with the DEF/Emissions system somewhere. Have you tried the handy "remove battery cables for 10 mins" trick to see if it does a reset somewhere with the computers?

 

[90kpaperweight]

I wouldn't say that you are guzzling DEF... many people on the forum seem to be averaging 1000-1400 miles per DEF Gal.

As I haven't experienced this first hand, I can't give any exact advise, but my gut says something with the DEF/Emissions system somewhere. Have you tried the handy "remove battery cables for 10 mins" trick to see if it does a reset somewhere with the computers?

Thanks @BrokerThis . I was basing the DEF consumption as compared to what my 2011 F350 consumed. Good to know that the consumption is not out of line for the GMC. I did not try the ol' disconnect the battery trick. The dealership has had it for over a month now. Maybe the battery will die in wait and the test will take itself.

 

[90kpaperweight]

I'd wager there's something wrong in the emissions system. Back pressure issues, sensor issue, plugged for some reason, manufactured wrong, etc. Maybe an injector that is dumping fuel.

My thoughts too @B-train I have asked if they have looked at the DEF tank and sensor. Of course they have not and are for some reason fixed on the cam shaft. I wish we could temporarily disable the emissions limp systems to see if that fixes the problem. My only complaint about diesel is all the emissions equipment that only has to do with cleansing the exhaust and nothing to do with the vehicle functioning. Don't get me wrong, I like the clean air and not a fan of the coal rollers we see out there but when the emissions mess with the operation of the vehicle is where frustration sets in.

 

[OR VietVet]

Welcome to the forum from Oregon.

Don't see why the strike would effect pencil pushers and the GMC rebuy.

I hate what you are going thru but all these new vehicle problems make me really glad I own my GMT800.

 

[90kpaperweight]

Welcome to the forum from Oregon.

Don't see why the strike would effect pencil pushers and the GMC rebuy.

Hi @OR VietVet .The rebuy would require a like new vehicle being available. My concern is that the strike will limit the new vehicle availability therefore making a rebuy more challenging. I already do not see my build really anywhere nationwide. Black exterior, tan interior, second row bucket sets.

 

[OR VietVet]

Hi @OR VietVet .The rebuy would require a like new vehicle being available. My concern is that the strike will limit the new vehicle availability therefore making a rebuy more challenging. I already do not see my build really anywhere nationwide. Black exterior, tan interior, second row bucket sets.

That color combo is jinxed. Do you have a second option?

 

[90kpaperweight]

That color combo is jinxed. Do you have a second option?

Jinxed @OR VietVet ? This is my wife's car so ultimately the color combo is her choice and I am interested to hear your thoughts on that combo we have now.

 

[OR VietVet]

Happy wife, happy life. Her vehicle, her choice.

 

[DuraYuk]

With the messages your getting its most likely something with the DEF system. It thinks your running out or don't have any so it's reducing engine power.

 

[90kpaperweight]

With the messages your getting its most likely something with the DEF system. It thinks your running out or don't have any so it's reducing engine power.

Thanks @DuraYuk I think it is something to do with emissions too. Just to be clear, it does not reduce power. The engine completly dies. It turns off. We have to pull over and restart the engine when it happens.

 

[OR VietVet]

Is it a form of saving the engine from catastrophic failure? I very much doubt it because that could be dangerous in certain types of traffic. The dealer has had it for a month and in all the land, yours is the only one doing this? There should be a TSB about this by now, unless your rig is the first to do this and then you will be the start of a TSB.

 

[DuraYuk]

Thanks @DuraYuk I think it is something to do with emissions too. Just to be clear, it does not reduce power. The engine completly dies. It turns off. We have to pull over and restart the engine when it happens.

Yeah I know what you mean. I'm thinking it sees no def and starts taking away power and it's shutting off. Wonder if it's a software anomaly. If TAC is involved there's really not much more you can do. They have every resource at their disposal. And when I was a tech I never had someone on the TAC line not know what they are doing.

 

[steiny93]

I was a tech I never had someone on the TAC line not know what they are doing

My wife's diesel denali has had a TAC case open since Dec of 2021. I'm supremely unimpressed with their ability to fix anything out of the ordinary.

 

[DuraYuk]

My wife's diesel denali has had a TAC case open since Dec of 2021. I'm supremely unimpressed with their ability to fix anything out of the ordinary.

What about ? You haven't fixed it in 2 years?

 

[90kpaperweight]

Update to this post. Still no diagnosis from the dealership, they nor GMC TAC can figure out the issue. GMC keeps saying they will not do a buyback without a diagnosis. Catch 22.

 

[StephenPT]

Where do you buy your DEF? I'm in-line with DuraYuk here that it seems to be related to emissions de-rating the engine. Turning off the engine at 50% throttle output doesn't sound right though, but there could be a bit more going on.

The DEF tank has a quality sensor and will determine the opacity of the fluid. If it doesn't like what's in the tank, it will de-rate the engine and throw a code. I would first make sure you have clean DEF in the tank.

I really would like to know what made the dealership think to go after the camshaft position sensor. That is a difficult part to remove and if IIRC requires the cab to be removed. Some dealerships were replacing the cam sensor back when there was a crank-no-start issue, which was later resolved via a software update.

Ultimately, it's your rig and you can decide who works on it. I would not leave it at that dealership if they are being incompetent and not making any headway on the issue. I know it usually doesn't help to be a difficult person to deal with, but often the squeaky wheel gets the grease...

 

[90kpaperweight]

Where do you buy your DEF? I'm in-line with DuraYuk here that it seems to be related to emissions de-rating the engine. Turning off the engine at 50% throttle output doesn't sound right though, but there could be a bit more going on.

The DEF tank has a quality sensor and will determine the opacity of the fluid. If it doesn't like what's in the tank, it will de-rate the engine and throw a code. I would first make sure you have clean DEF in the tank.

I really would like to know what made the dealership think to go after the camshaft position sensor. That is a difficult part to remove and if IIRC requires the cab to be removed. Some dealerships were replacing the cam sensor back when there was a crank-no-start issue, which was later resolved via a software update.

Ultimately, it's your rig and you can decide who works on it. I would not leave it at that dealership if they are being incompetent and not making any headway on the issue. I know it usually doesn't help to be a difficult person to deal with, but often the squeaky wheel gets the grease...

Hi @StephenPT I only buy brand name Peak Blue DEF. I heard of others buying cheap WalMart stuff and having issues so I spend the extra $$ to avoid any quality problems. The cam shaft sensor did not sound like something easily replaced. The more they wrench on and take apart the NEW vehicle, the less we want that one back.

 

[StephenPT]

So you have 10K miles on this rig, right? There's another forum member here that had a basically brand new '23 Yukon and received a "Service Emission System" error code - I think within the first 500 miles. No noticeable signs of drivability issues, so he kept going and the code went away. I also lurk on the "Duramax Forum" where there's more activity because it tends to get the crowd that runs this LM2 motor in the pickups and have not seen many, if any, issues come up related to the emission system de-rating the engines. Your issue is the first time I've heard of it shutting down the engine.

If you browse a bit on this forum you'll see there's a handful of other members that have had to deal with buybacks from GM. Overall it seems to work out in the end for everyone, but it's not a pleasant process. I believe all of them up to this point have involved the 5.3 or 6.2 gas engines and their repeated valve train failures. I think a few others had early production '21's that were just lemons out of the factory. If you read through those threads you'll see everyone has to start playing a bit of hardball with their dealer and/or GM support team. Lemon laws vary by state, so you'll need to do some research of your own, but you might be able to find a lemon law lawyer that wants to get involved in your case and it seems once they do, suddenly GM makes your case a priority and it either gets fixed or you get a buyback.

I hope you get resolution soon - take care.