2007 Yukon Denali stalling

[wjburken]

Thank you so much for your info, and your greetings, back to you I will be having the work done by a very qualified mechanic, and I will have the things replaced that you have suggested and see if this issue can be finally dealt with. Thanks again!

Sounds good. Please report back with how things workout.

 

[BG1988]

No trans codes are present current or history. I can read all the pressures at all 6 solenoids among other things but my scanner cannot actuate or run any cleaning commands to them. Sitting there idling, all items monitored were within range per my scanner, FWIW. I’ll keep it hooked up next time I’m out with it and have the live data up when I know it will stall.


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check the power connections mine was acting up transmission was playing dead.

basically it would not go, i had to keep the rpm at 1,000 just to keep it from stalling out..

check and see if there is any stressed cables those are the ones that have the bad connections

today I had adjust the power cable (released the stress by giving it some slack by adjusting the battery location slighty) as it's internally damaged.. these NNBS are sensitive to issues with the power cables and the power delivery(as they made changes to the NNBS) but i know for sure mine are damaged.. I messed with them abit you can see the cable suffered major damage...from an accident (that the dealer lied about)
it takes a ton of force to get those crimps apart.


i'll be ordering new cables soon hope the damage is limited to just the break out cable (39$)as the second part of the positive power cable is $250 just for a Proprietary electrical cable
i can afford to buy it but rather use that 250$ for something else like maintenance or new shocks in the rear

 

[vettes980]

check the power connections mine was acting up transmission was playing dead.

basically it would not go, i had to keep the rpm at 1,000 just to keep it from stalling out..

check and see if there is any stressed cables those are the ones that have the bad connections

today I had adjust the power cable (released the stress by giving it some slack by adjusting the battery location slighty) as it's internally damaged.. these NNBS are sensitive to issues with the power cables and the power delivery(as they made changes to the NNBS) but i know for sure mine are damaged.. I messed with them abit you can see the cable suffered major damage...from an accident (that the dealer lied about)
it takes a ton of force to get those crimps apart.


i'll be ordering new cables soon hope the damage is limited to just the break out cable (39$)as the second part of the positive power cable is $250 just for a Proprietary electrical cable
i can afford to buy it but rather use that 250$ for something else like maintenance or new shocks in the rear

View attachment 238334

The amount of electrical gremlins in these trucks is maddening! My issue is pretty easy to replicate and only happens warm and when coming to a stop. If it’s a transmission going I will pry just say goodbye to it. Hopefully it’s a TCC solenoid or bad converter at worse. I now wish I was on here before I bought my Autel Scanner as I can’t run the diags on the transmission system like the Tech2 can.


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[swathdiver]

The amount of electrical gremlins in these trucks is maddening! My issue is pretty easy to replicate and only happens warm and when coming to a stop. If it’s a transmission going I will pry just say goodbye to it. Hopefully it’s a TCC solenoid or bad converter at worse. I now wish I was on here before I bought my Autel Scanner as I can’t run the diags on the transmission system like the Tech2 can.


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Get a Tech-2, lot less expensive than a new car or throwing parts at it. Or, where do you live? Maybe someone here lives nearby and has one?

 

[TsaWind]

Hello, I signed up here just to post on this thread.
I too have a 2007 Yukon XL Denali 6.2L currently 175k, bought with front end damage at 140k
We have had stalling issues.

This is going to sound crazy...
I believe you are vapor locking.

We had to wrap our fuel rail with insulation because our truck would stall when coming to a stop on summer days when pulling a trailer with weight. There are probably many other fixes, but basically the fuel rail got so hot that the gas inside it turned to a vapor, increasing psi and causing the motor to only restart after if cooled off.

After we solved this we drove for about a year without a stall.
Then we had to install a new VVT bolt thingy, we are on our second cam sensor and first crank sensor replacement.
Drove for over a year without a stall.

 

[swathdiver]

Hello, I signed up here just to post on this thread.
I too have a 2007 Yukon XL Denali 6.2L currently 175k, bought with front end damage at 140k
We have had stalling issues.

This is going to sound crazy...
I believe you are vapor locking.

We had to wrap our fuel rail with insulation because our truck would stall when coming to a stop on summer days when pulling a trailer with weight. There are probably many other fixes, but basically the fuel rail got so hot that the gas inside it turned to a vapor, increasing psi and causing the motor to only restart after if cooled off.

After we solved this we drove for about a year without a stall.
Then we had to install a new VVT bolt thingy, we are on our second cam sensor and first crank sensor replacement.
Drove for over a year without a stall.

Welcome Travis and thanks for posting that fix.

 

[vettes980]

I’ve confirmed my stalling is transmission related. Not sure what the final resolution will ultimately be, but I have corrected the stalling with a bottle of additive given to me by my local transmission shop. I’m hoping a few weeks of driving with this additive and then a filter and fluid change will prolong the life. Still not sure if it’s a converter, valve body or solenoid.


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[Brandonshane74]

I’ve confirmed my stalling is transmission related. Not sure what the final resolution will ultimately be, but I have corrected the stalling with a bottle of additive given to me by my local transmission shop. I’m hoping a few weeks of driving with this additive and then a filter and fluid change will prolong the life. Still not sure if it’s a converter, valve body or solenoid.


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Did the additive help with stalling? Mine is doing the exact same as yours. I’m at a loss. I’ve but the additive in and it makes it harder to stall but I can still make it stall.

 

[vettes980]

Did the additive help with stalling? Mine is doing the exact same as yours. I’m at a loss. I’ve but the additive in and it makes it harder to stall but I can still make it stall.

The additive stopped my stalling for 5 months. I then changed the fluid and added another bottle of this additive and trouble free driving for 2500 miles. Long trips short trips, normal trips and no issues.


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[upnorth76]

I hope this helps some of you...


Ok people. Here it is. The REAL PROBLEM for me and most likely for 90% of you out there is this!!!

Bit of background. I’m a licensed tech in Canada 21yrs. Experience. Worked at Dealerships for 17 years including GM for 4yrs.... anyway....

My truck: 2007 Denali: 6.2L - 6L90 trans. 385,000km ( 240,000 miles )

First, my symptoms: random stalling/ NO RESTART after towing/HOT. Then after awhile random stalling NOT TOWING, turning left/right etc...
At first wasnt setting any codes other than a random shift solenoid code in trans. Then later on setting low oil pressure code P0521. ( prob have cracked o-ring on oil pick up tube )

Tried new fuel pump relay and thought I had fixed it... nope. Then replaced fuel pump w/ ACDELCO unit... thought it was good... nope.

THEN TRIED: cleaning battery connections, clean 175A fuse connections on pass firewall, checked PCM pins for backing out/ added dielectric grease to help prevent “ fretting” as/per GM TSB, removed underhood fuseblock/ JUNCTIONBLOCK, checked all pins in base mounted connectors/ looked good/ applied dielectric grease to all, added trans “ medic” additive to trans fluid, test drove to get trans to oper. temp. then serviced trans. using proper fluid ( this is to address the issue related to suspected TCC CLUTCH/ solenoid/ valve sticking ) I didn’t suspect this because when that happens you get a noticeable LURCH/Bucking when Yukon stalls out and I think most people ( including me ) aren’t getting the lurching/ stalling.
ALSO added GUNK ENGINE FLUSH and 1L ATF ( atf in engine crankcase is a great cleaner because atf contains lots of detergents ) to crankcase to flush engine lube system. This was to address possible VCT valve/ phaser sticking causing stalling after coming to stop from hwy. speed/ heavy loaded condition. Serviced engine w/ 0w40 Mobil 1...

DID ALL OF THIS IN ONE NIGHT... because I didn’t have time to mess around doing it one at a time to see what fixed it... ANYWAY... NOTHING WORKED. Drove for long test drive at high speed, seemed ok, thought it was fixed, wife was driving it two days later in stop and go traffic and it stalled again.

This time ENGINE POWER REDUCED MESSAGE AND ENGINE OVERTEMP. MESSAGE CAME ON IN CLUSTER.

So then I finally broke down and fixed what I suspected to be the REAL problem all along but is really EXPENSIVE!!

Faulty underhood fuse block w/ integrated PCB ( printed circuit board ). Circuit board cracks, and various circuits open up when underhood TEMPS get HIGH!!

Costs $850+tax at the dealership in Canada. Will cost you about $600 in the U.S.

Replaced this and haven’t had any problems since then.

Have had TONS of issues which these while working at the GM dealer but didn’t want to try it first since they are pricey $$$.

Fixed stalling issue and reduced power message etc...

I think this is probably the problem for most of you guys... I Hope this helps someone.