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Posted

Calls for a reprogram of the ecm and tcm.  

  • GM Recall #:
  • N212354170
  •  
  • Date Issued:
  • Mar 17, 2022

Recall Title:

DPF Regeneration Temperature

Recall Description:

General Motors has decided to conduct a Voluntary Emissions Recall to improve the operation of the regeneration cycle on certain 2020 Chevrolet Silverado and GMC Sierra vehicles with a 6.6L diesel engine. The recall will address that currently under certain operating conditions, higher than necessary temperatures may be used to clean the Diesel Particulate Filter (DPF) during the regeneration cycle.

 

Repair Description:

Dealers are to reprogram the Engine Control Module (ECM) and Transmission Control Module (TCM).

  • Like 1
Posted
3 hours ago, kmonto said:

How do we know we are impacted?  Is this for all 2020 HD diesels?

Yes, for all 2020 6.6 duramax diesels.  My truck has shown no signs of an issue with this yet, but it will go in for the recall next week.  

Posted

Had mine done last week.  Have not noticed any difference in operation.  

Posted
10 minutes ago, kmonto said:

Got my scheduled but they stated I needed a card to show that it is needed.  Any ideas?

Go to the gm recall center online and enter your vin.  It should pull up the same info I copied here above for recall number N212354170.  You can print it out and take it with you.  

  • Like 2
Posted
1 hour ago, shadow gray 2020 hd said:

Go to the gm recall center online and enter your vin.  It should pull up the same info I copied here above for recall number N212354170.  You can print it out and take it with you.  

 

I did but my vin shows no recalls at all.  zero.  Maybe that is why she asked for me to bring the card in there.  Either way, we will see if they do the work.  Thanks for all the info though.  My truck is a 2020 2500hd 6.6 Diesel LTZ 4x4.

Posted

I got the recall done a couple weeks ago and there is a noticeable difference in the way it drives. It operates like it is in a constant regen cycle. It holds lower gears more often, keeping the RPMs higher and lowering my fuel economy. It is also more aggressive on the downshifting when I let off the accelerator. This is how it felt during the regen cycle prior to the tcm update, except it happens all the time now. I verified with a scanner that I am not in a regen, i was at about 85% soot level.

 

Stop and go traffic around town would get me around 14 to 15mpg before. Now, I am getting 11 to 12. On the highway at about 70mph, I was easily getting 20mpg or more. Now, it is more like 18 to 19mpg.  I hope the transmission is still trying to figure things out and will get better.

  • Like 1
Posted
22 hours ago, kmonto said:

So do I really want this done if it kills my mileage...

Alternative might be that the def tank overheats and causes other problems with the def system.  Some horror stories about people waiting for parts for their trucks right now related to this issue.  Taking my chances with mine and having them do the recall/reprogram.  If my mpg's take a hit, I will take it back to them. 

 

fwiw, about every 2-3 weeks my truck's efficiency takes a major hit, and then after a couple days driving goes back to normal.

  • Like 1
Posted

I had mine done on June 1st and I haven't noticed any difference in mileage or drivability.  I towed my 8,000 lb Airstream trailer 300 miles on Tuesday and will be returning home tomorrow.  Towing was normal and I averaged 14 mpg on the outbound trip.  I expect the see a regen on tomorrow's return trip and we'll see how that goes.

Posted

Just got my recall notice in the mail.  I also checked the infotainment system and the recall was shown there.  My appointment is scheduled for next week.  We'll see........

Posted (edited)

I too get worse efficiency.

 

I was getting 19-21mpg on the interstate.  After the recall, I'm getting 17-18mpg on the interstate.

 

I should have read the forum prior to doing the recall.  

 

Thinking I should go back the dealer and remove the recall, if possible.

Edited by tbmachado
Posted

I had to reschedule the recall on my truck until this morning.  I am thinking the tcm part of the "upgrade" has some issues. My truck on the way home felt like it was in tow/haul mode and my mpg's have taken a substantial hit.  After the issues with the brakes, the dealership seems to be getting irritated.  Hate to have to take it back, but does not seem right and the damned thing cost too much money not to be right.  

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