2021 6.2L Yukon Denali Dead Battery Gremlin? Not the truck?

[TheAgency]

I have had this truck since day one, 60k miles problem-free. I buy a new truck every year/every other year for business tax purposes and recently gave this older one to my mother (also an employee of mine).

Since she got it, truck has died in her garage 3x times. Completely dead battery. Started with the obvious and put in a new Delco battery. Dead again in a week. Dealership warrantied the battery. Dead again in a week. Tested for parasitic draw, nothing and sent it back to us. Dead again. Parasitic draw tested again, they kept it for a week, and fired up for them just fine. They say the truck is perfect and up to date on software. Checked all TSB's off. It's a great dealership and the most senior tech's looked at it— I believe them.

Dealership and I are thinking its something in the house or something she's doing. (She's a smart gal, she's not doing something obviously stupid).

Garage door opener interference? We're crossing things off, but curious if anyone had any suggestions or similar experiences.

 

[Fless]

As a test, put all the key FOBs in a Faraday bag, far away from the truck when it's parked. I've heard that the FOBs "check in" if they are within range, even if the truck is parked.

I wouldn't think that a GDO would have anything to do with it, but what make and model is in her garage?

 

[B-train]

I'd try parking it in a different area for a few days. Maybe not in the garage. And put the fobs far away

 

[StormTrooprSubZ71]

Is it sitting for a week without starting? If the keys are too close the truck does detect them and "wakes up" turning on the lights.

 

[Stbentoak]

I don’t think this fob to close thing is true. Mine sit within 10 feet of my truck ( other side of wall) and have for the whole time I’ve owned it…..doesn’t do a thing..
The only real way to know is start pulling fuses on unneeded features till you pin it down or have a way to monitor the BCM all the time for what’s pulling on it…
Or maybe the app is checking it continually and needs to be shut down or deleted and re established…

 

[StephenPT]

Check out this thread - https://www.tahoeyukonforum.com/threads/2023-tahoe-premier-battery-issue.145303/page-3#post-1841941

Similar dead battery issue - dealer couldn't figure it out at first, but ended up finding the liftgate module wouldn't go to sleep, so they replaced it.

As a quick test you could locate pull the fuse for the liftgate module - it's F35RA - back in the cargo area fuse panel. Reference this TSB for more info. https://static.nhtsa.gov/odi/tsbs/2023/MC-10231664-9999.pdf

A lot of people suggest hiding the FOBs - my wife often leaves her purse inside the Yukon when it's in the garage. It sometimes will go over a week without us driving it. Always fires right up the next time we go to use it. I don't think the FOB theory has any merit. I'd be willing to bet one of the modules (likely liftgate module) is not going to sleep properly.

 

[B-train]

Agree with the FOB stories, just figured I'd throw it out in case it has a stuck button or something trying to communicate. But, to your point, my wife leaves hers in her yukon all the time, sometimes for a week or more. It always starts.

But, I did find out that if the FOB battery is weak and the truck doesn't sense it, it will lock your keys inside for safe keeping.....

 

[WalleyeMikeIII]

The only possible thing that could be FOB related would be if possibly you had the fobs hanging on the back of a door that is openeing and closing, and just close enough to the vehicle that the vehicle thought it was a someone walking up to the vehicle, and doing its initial walk up wake up...but...seems like you would have to do it an awful lot to kill the battery.

There has to be something not properly going to sleep on this ride...

 

[TheAgency]

In a super wild turn of events, we have lifter failure at 60k miles. Possibly from all of the hard and incomplete starting? An otherwise perfect truck with no issues, one that has seen nothing but AmsOil Signature oil every 5k.

I was just under the 60k mark for warranty and the dealership had one of their HD guys work on it. All 16 lifters were replaced in 1 day. Truck was done and running smooth before they could have a chance to call me with a diagnosis.


This thing has been suddenly crazy to say the least. 10/10 Dealership service experience.

 

[WalleyeMikeIII]

In a super wild turn of events, we have lifter failure at 60k miles. Possibly from all of the hard and incomplete starting? An otherwise perfect truck with no issues, one that has seen nothing but AmsOil Signature oil every 5k.

I was just under the 60k mark for warranty and the dealership had one of their HD guys work on it. All 16 lifters were replaced in 1 day. Truck was done and running smooth before they could have a chance to call me with a diagnosis.


This thing has been suddenly crazy to say the least. 10/10 Dealership service experience.

Are they chalking up the battery drain issue to the Lifters? Or did you never get the battery issue solved?