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Dead Battery - couldn't jump it

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Had the first "major" issue with my 2020 this week.  The battery died on my 2500 gasser.  Has anyone else had this issue?  Didn't show any signs until one day the truck wouldn't start.


  • Jump box didn't work.  Turned over once or twice, but that's all.
  • Overnight on the trickle charger did nothing.
  • Jumping from my neighbors 3500.  Turned over once or twice again, but not quite.
  • Other neighbors bigger jump box didn't work.


Put in a new battery and it fired right up.  The old battery was sloshing around a bit when I pulled it out.  I've only seen that on flooded RV batteries, which this is not.  Hope I'm not buying another battery in 19k more miles.

Also, the battery cover was a pain to take off.  So much room in the engine bay and they couldn't make the battery change 20% easier?  Stupid engineers.

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I have a feeling these trucks are going to eat batteries, as they seem to have  a lot of offline current draw. I let my Duramax sit for 6-days, and checked battery voltage before I started it.  They were both at 12.28.  I didn't think it was going to start, but it did.  I am having intermittent CEL issues and thought it might have been caused by low voltage.  CEL did not come on this time.

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Had a battery issue with mine  wouldn't start, thru a glow plug code plus some others.  According to the dealer battery's were fine the codes were caused by the low voltage. During the winter my truck might set for 4 or 6 weeks at a time. Now I keep it plugged in all the time, Battery Tender JR. keeps voltage at 12.95 V. or better. 

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20 hours ago, MTU Alum said:

There is a service bulletin out about a wire being chaffed behind rear seat.  This can cause the LIN bus to not shut down and drain your battery.



can you post the bulletin?

this is something most of us could probably check at the house


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  • 3 weeks later...

2020 2500 HD Diesel


I had a similar problem after not driving for a few weeks.  I had a radar detector plugged into the lighter port, but I assume this cuts power.    The batteries were completely dead and I had to use the emergency key to unlock the truck.  This triggered the anti-theft.   I put a battery charger on the car and it couldn't charge because the truck was trying to flash the lights and honk the horn.  I was able to jump start it after leaving jumper cables between two vehicles for 45 minutes.  


The dealer replaced both batteries, but didn't correct any TSB's.  

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