2023 Duramax High Country, less than 1 month old, approx 2200 miles. periodic check engine light and 2 instances of “limp mode” (top speed of 62mph). Went to start this afternoon and wouldn’t crank but flashed every warning message possible. 30 min later, started, drove 2 miles and died, again flashing every warning message. 45 wait for tow, and driver was able to start and put on back of flat bed. Transmission warning seemed to be prominent. Thoughts?
Dead on side of road
- Thread starter dc968
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DuraYuk
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Hard to say without diagnostic codes. Just feeling the magic in the air maybe alternator ? Haven't heard of any crippling catastrophic issues regarding lm2 like you describe. You may be the first ! Sorry for your luck. Let us know what happens.
66 Galaxie
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Maybe a bad battery
DuraYuk
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Cars run off the alternator not the battery.
Seamus
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Bad battery. Bad alternator. Loose connection at starter. Loose terminals. Ground. These new vehicles go nuts on a bad battery or bad connection. Keep us updated.
Electrical for sure but with all the stuff they cram in them now days, I have not got an intelligent clue. Battery seems to be the consensus.
BrokerThis
'22 Denali Dmax
@dc968 did you push the onstar button and have them run a diagnosis and email you the results? Assuming you still have a CEL showing
When I went through my ordeal, my truck threw ALLLLLL kinds of crazy messages. When I say all kinds of messages, I mean ALLLLLLL kinds of messages like lower and raise the window, liftgate glass open (it wasn't), etc etc.
Took it to the dealer, they found a loose connection at the battery.
I am hoping it is something loose and that's it. Best of luck.
Took it to the dealer, they found a loose connection at the battery.
I am hoping it is something loose and that's it. Best of luck.
Back in the 70’s and early 80’s I could start a car pull the battery and drive that thing as long as it stayed running so yes that statement is semi true. Back then the alternator took a lot of abuse and they weren’t very high amp alts 50,60 maybe 70 if lucky..so using wipers or heat and headlights you could tell it was trying to keep up with the electrical load.
With all the electronics and computers on any newer model vehicle if your battery is even a few volts off or you have a loose connection it will play havoc on these systems even with a 120,150,170 amp alternator.
It’s very important to keep connections tight, grounds clean and solid and batteries fully charged.
Your statement was true 30 years ago and to an extent but not so much today.
Very strange for a Duramax.
But it’s really not the engine that’s the problem… it’s all the electronics making that engine run…or not run in this case.
I did not ask them to run a report. Didn’t think to. I did use the button to call roadside and get a flatbed.
Onlyone
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A battery starts the engine. Not the alternator. The alternator keeps the battery charged. Without a good battery the engine and all the electronics will not work correctly. So no, the alternator does not “run” the engine, as soon as it dies or tried to restart, the alternator is useless without a battery. With all the extra voltage requirements these new vehicles need, it’s no wonder that we see so many battery issues.
So after a number of update calls from local dealer (not where I bought it) keeping me up to speed on what they were chasing down w/GM I’ve been told the problem is a faulty electronic brake controller module. Part is apparently back ordered. They told me at least 2 more weeks To get part. I’m in a new LS loaner at least so have the space but none of the options. Hopefully this fixes the issue.
DuraYuk
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The alternator runs the electrics and charges the battery. So yes it does absolutely run the car. https://www.thedrive.com/tech/7298/what-does-a-cars-alternator-do
Weird that his issue Is attributed to brake controller. We will see if that's the fix.
Onlyone
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Go away silly little troll. Stop parroting. Your mom called you up from her basement for dinner.
DuraYuk
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Shut up and learn something. All your posts are bs people come here to get real info not your false answers.
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Onlyone
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Bye troll. Everyone knows who you are. Don’t go away mad, just go away.
DuraYuk
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Dude you need to grow up. Don't get mad. It's not a popularity contest. Just a matter of who's right and who's wrong. I'm also not sure why you even comment on the 21+ forum when you have no experience with the platform.
You don't add anything meaningful to the discussion except wrong answers. And then clutter the post with name calling like a little kid.
Alternator runs the car and charges the battery. The battery only exists to start the engine. An alternator can keep a car running by its own voltage output. Battery has nothing to do with that except to be a load on the circuit when vehicle is running. If a car is started and battery dies because of a bad cell etc the car won't just die. Why do you think an alternator puts out more than 12 volts? Gotta know what your talking about. Now if an alternator dies while the car is running the car will die as soon as the battery dips below 12v.
But whatever dude over here knows things lol..smh
Here's another link to clear it up for you. It has pics too. https://theengineeringmindset.com/car-alternator-how-alternators-work/
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