Jump to content

2021 Sierra 1500 AT4 issues

Leslie Politron
 Share

Recommended Posts

Frustrated Chad Enthusiast

Frustrated Chad

Posted
Posted
On 8/9/2021 at 3:22 PM, Rhino83 said:

Cel was on for 2 days and then off. Drove all last week with no cel but made an appointment to have it checked out again. Dropped it off today and they are looking at replacing the ecm since they updated it last time, but truck is running fine. Still tripping the p0300 code so no changes there. Luckily got a loaner to drive which is a Buick envision lol but at least at not walking. Will update when I get the truck back and let you know what they did.

I have driven so many loaners I could be an expert on other vehicles not to buy. Lol the most comfy was the enterprise rental they had to get me - 21 Tahoe. The gmc 21 acadia was nice and sporty/peppy (v6) both way better than the envision and a smaller one I think. Truck has been in shop since last Tuesday. No update yet. Did hear from the head tech/ mechanic they are going to offer me an additional extended warranty for the motor. Not sure how long though. If it happens again after this time we are getting a lawyer. I will be done, sad but done!! I love the truck but can't drive something I don't trust. 

  • 2 weeks later...
  • Replies 36
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Posted Images

John Mcrae New Member

John Mcrae

Posted
Posted
On 4/9/2021 at 6:01 PM, Leslie Politron said:

Hi. I bought a new 2021 AT4 March 5. 20 miles on it. Drove home from the dealer (4 miles) and the next time I turned it on, CEL and OnStar diagnostics emails me to take it to the service department. They say they reset MAP sensor and send me on my way. Later that day, same thing happens. I take it back in, they say MAP sensory needs replacing. They had it almost 2 weeks waiting on the part. After they replaced it, everything went fine for about 1200 miles and then I get blinking CEL for about 30 seconds then it stops. Next day, blinking CEL for a minute or so, and then it turns solid. I took it back to the dealer and they say the only code pulled was P0300 misfire. They have no idea what’s causing it, and quite frankly I’m pretty fed up at this point. They’ve had my new truck longer than I have in the month I’ve owned it. Has anyone had something similar happen?

098552EF-4C86-4348-A162-38FD4190B875.jpeg

I'm in the same boat as you. Same code and the first parts they changed were the lifters, only had 1600 miles on it. Now it's back in the shop and they don't know what the problem is. Just throwing parts at it. Very dissatisfied with the product and dealership won't swap it for a new one without paying at least 5000.00 more. Are you kidding me. May have to shame this dealer into a deal that works for me.

Frustrated Chad Enthusiast

Frustrated Chad

Posted
Posted

Latest update. Truck was in shop for 3.5 weeks. Think it was being used as a guinea pig by the GM engineers. App could not connect to it the whole time. Said there was something plugged into the diag port. Picked up today. Told to drive regardless of cel coming on. Per fm engineers. My karen(used to be a karen in her old days, not like the ones you see today but didn't take sh@t!) LOL we requested in writing that it was ok to drive with cel on. Denied. Told them we have lost faith in vehicle. I don't trust it if I have to travel for work. Mentioned buy back and lawyers. Got to see the dealership GM rep. Verbally agreed no issue if l

Cel comes back just keep them updated. Agreed. They are going to ask gm Corp to give us 72/100k for warranty. Plan b is if issue is still not resolved in a few months, vehicle swap basically. So we shall see how this goes. Just not looking forward to possibly getting lawyers engaged. Have me and the boss some piece of mind. As it stands we have had the truck in our possession 50%of the time since March. Want reviews on other vehicle models got me up. Acadia, numerous buicks, even a Tahoe that was an actual rental. Truck mfg date was last year so I think it was worked on by a mechanic building it with covid.  Lol truck is sick just like the world today! 

Rhino83 Enthusiast

Rhino83

Posted
Posted

Sorry for the delay since my last post on August 9th.  Update as of August 24th.  When I took it in, on the 9th, they were discussing replacing the ECM or doing another update on the ECM.  Come to find out, did neither.  Was told the ECM update that was done was for 5.3 V8s without the 10 speed transmission and that GM was working on an updated ECM software for the 10 speeds.  Have not had a CEL since July 30th so fingers crossed my worries are over but still guarded.  I'm approaching 3K miles so we will see.  Service Tech even showed me the bulletin about the updated ECM software regarding 10 speed transmissions.

  • 5 weeks later...
Frank 2021 New Member

Frank 2021

Posted
Posted

[2021 GMC Sierra 1500 AT4 - 5.3L ECOTEC3 V8 W/DFM - currently @ ~3676 miles - purchase NEW this past May 30, 2021]

 

After the first CEL occurring within two weeks of purchase (see previous comment on page 1 blaming old winter grade fuel) I have driven this truck all summer long (having put premium gas in once or twice shortly after first servicing) with several trips to the beach (including 4wd on the beach) no issues ... but a second CEL occurred two weeks ago (first week of Sept) after a long idle in line for a child pickup after school. It disappeared on it's own a day or two later. Just had it serviced along with another issue where my passenger window would roll back down after I rolled it up. (Sidenote: I did get a base model 2018 Silverado as a loaner but I ended up getting the truck back same day. - Better loaners were promised me by the sales manager after some dealer errors on the purchase day. Not sure that Silverado qualifies, but I digress.)

 

Written on the service order was the following:

"... DTC P0300 with cylinder 1 & 6 misfire counter history at 130 and 232 misfire counter and number of other cylinder with small amount of misfire counter history"

 

Since the CEL was no longer on they also documented this:

 

"No misfire detected ... Recommend reprogram ECM with latest calibration and relearn crankshaft variation Doc ID#5869744"

 

I don't seem to be getting the quite the same feedback from the technicians as some of the others here, not sure if that means they are being coached to not say it but I guess I'll see how long this "fix" will last.

  • 9 months later...
James Goodin New Member

James Goodin

Posted
Posted

Took my 20 AT4 to service dept due to heavy stuttering.  Said that’s what the 10speed tranny does.  I said yeah til it gets me killed in traffic.  Took back a 2nd time and they want to replace the ECM.  But it’s on back order with no eta and they won’t give me a loaner.  Only 20k miles.  Really frustrating!!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Chuck FB
      OCI, not when but why?

      By Chuck FB · Posted

      I imagine the cold winters up here with repeated short runs in town every day for those that live and work in town and given what I have come to learn on this forum with DI engines having fuel dilution issues, and if they don't change the oil until it says to but keep driving it for a while, I bet all that is just lovely on those finicky lifters. 
    • teamjnz
      AWD conversion to Z71

      By teamjnz · Posted

      I just did some reading and Stabilitrak is more than a what I had originally thought. It is more of a vehicle control system to help the driver in precarious situations. I thought it was only the AWD system. Now I know. So I changed the title for this thread to AWD conversion to Z71 
    • teamjnz
      AWD conversion to Z71

      By teamjnz · Posted

      Sounds like converting will be a bigger endeavor than I was thinking. This truck doesn't have 2Hi like the Suburban did. The Tahoe has 4Hi and 4Lo and a button to turn of traction control.   From what I understand the Stabilitrak uses open diff in the front and rear. When wheel speed is not the same the stabilitrak uses the ABS system to slowdown the spinning wheel(s) to transfer power to the slower non-spinning wheel(s). I thought the transfer case was open too. Being able to transfer power either more to front or rear depending on wheel spin. Maybe I miss understood some information with you saying and power transfer is 50-50. Thanks
    • PunchT37
      OCI, not when but why?

      By PunchT37 · Posted

      My brother has a 2007 Avalanche with afm 5.3. It`s got 176,000 miles. Runs like a clock. Never been apart. Co worker has a 2010 Tahoe with afm 5.3. 230,000 miles. Never been apart. Runs like a clock. So, even though cyl deac is a weak spot, they can go the distance.   BUT, these engines had the oil changed regularly, AND had 5w30 as spec. I wonder if they would have lasted this far on 0w20? I`ll bet not.
    • Chuck FB
      OCI, not when but why?

      By Chuck FB · Posted

      I certainly could be wrong but I hear of pickups far newer than that 2007 cutoff which may not be going to the wrecker but are having engine work done and be that a reman engine or new engine or trying to repair the existing engine. Some of it would be design issues as per the cylinder deactivation system that GM has and one of those lifters wiping out the cam and the question of oil changes moving the needle or not on that whole mess, or in the case of Ford pickup engines that have the long timing chains and wearing them out and the roller followers and phasers and some of that certainly goes back to oil change intervals. But in those various cases the truck has all sorts of life left in it and so the unfortunate owner and may be original owner or used market owner that is pouring money into repairs so the truck is not seeing the salvage yard yet but damage is happening by infrequent oil changes. A friends son had bought a 2018 I think it is half ton GM and it had some sort of extended or used dealer warranty on it and of course the lifter issue bites and its rattling and so the dealer had to swallow the bill and was at least 7000.00 and I think they only replaced what they felt they had to replace so yeah, I can see that being a ticking time bomb in the not too distant future. Would frequent oil changes cure all these engineering "marvels", probably not but some engine designs have shown that they do much better if the oil is changed a lot more often then if the manufacturer service claims are followed. New trucks cost so much that there is an incentive to keep the existing truck on the road by repairing. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...