Jump to content

2021 Sierra 1500 AT4 issues

Leslie Politron
 Share

Recommended Posts

Dc7707 New Member

Dc7707

Posted
Posted

Bought new 2021 at4 in December and already had to get it towed back. From what I understand they have defective lifters which caused misfire and bent push rod… apparently they’ve known about the issue. Im considering using lemon law but its sad. I loved the truck but too bad the engine is ******. 

  • Replies 36
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Posted Images

Dirk13 Enthusiast

Dirk13

Posted
Posted
On 6/23/2021 at 11:50 AM, Kanon Morris said:

Ahh, gotcha.  That sort of answers a question I had.  I drove a 2021 elevation 5.3L that did not include the DFM (-$50 on the sticker).  I was curious if the actual hardware was removed, or if that was a software removal.  Sounds like GMC possibly removed the hardware?

I think it is highly highly unlikely gm changed anything at all other than omitting the component they have a shortage of, which is the electrical hardware for control of the system. Those trucks will still have the same hardware in the engine. 

Kanon Morris Enthusiast

Kanon Morris

Posted
Posted
8 hours ago, Dirk13 said:

I think it is highly highly unlikely gm changed anything at all other than omitting the component they have a shortage of, which is the electrical hardware for control of the system. Those trucks will still have the same hardware in the engine. 

 

I think you’re right.  I’m still perplexed why this 5.3L 10sp w/ DFM is so much more sluggish than the 5.3L 8sp w/o DFM.  It’s like a night and day difference that me, my wife, and my neighbor all recognize.

 

It’s my understanding DFM only drops cylinders at cruising speed on the highway, and not during takeoff.

 

Any idea why I could be seeing such drastic performance gulfs?

Frustrated Chad Enthusiast

Frustrated Chad

Posted
Posted

Truck back in for 5th visit but at my request. I just was not confidante in the truck. 20-40mph experiencing best I can describe is stuttering with acceleration. Only does this when cel is on. After a few days of no driving the cel will turn offand once or twice it would turn off while driving. Then truck would be normal, no issues. 

Anyway I called the service dept stating I'm not confident that the truck won't leave me on the side of the road again. Asked them to get me a loaner until they resolve the issue and truck should be there at the shop until then. 

They had no loaners, so they had to engage enterprise rental car. Driving a 21 white(yuk) Chevy Tahoe with less than 3k miles. First full size loaner the dealership gave me. 

Anyway the rental required approval from GM themselves per my service mgr. So if that's true, I'm hoping the engineers are actually working on the fix. Question is can I trust the vehicle after all this mess. 

 

Oddly my Facebook feed the other day popped up a post from some lemonlarry. Ad meant to look like a post I think. It was listing 19,20,21 sierras and Chevy. Guess they are trying to get a class Action going. Didn't click on it. 

Rhino83 Enthusiast

Rhino83

Posted
Posted

Same issue here.  Bought my 21 a month ago with 10 miles on it and last Tuesday got the Diagnostic email, text message and check engine light.  Took pics of all on my phone for confirmation.  Took to local dealer and they hooked it up to the code reader and tripped the p0300 code for random misfire.  Had 1100 miles on it last week.  Check engine light turned off while at dealer but they did not clear it.  Exactly one week later (yesterday), check engine light, email and text reappears with 1254 miles.  Took back to dealer and same code.  I have not noticed any rough idling or driving.  Very frustrating in deed for a $60K truck!!!!

Frustrated Chad Enthusiast

Frustrated Chad

Posted
Posted

Truck has been in shop for past 2 weeks. Told them I don't want it back until resolved. They had to rent a vehicle from enterprise for me to drive due to no loaners. Got the call this past Wed that the computer had been updated and I can pickup my pickup... we shall see, I have never heard of engineers getting code done that quickly. Lol fingers crossed. If anything else goes wrong the truck is going back and I'm getting my money back or demand upgrade to the diesel model. Lol

Rhino83 Enthusiast

Rhino83

Posted
Posted

Anyone discussing buy back? Any news on any updates? Anyone entertained a buy back? 3 weeks and 3 CELs and 3 p0300 codes with no updates.

Adamace1 Enthusiast

Adamace1

Posted
Posted (edited)

Hopefully they will figuire this out soon. It can be a good motor. I haven't had any problems in my first 15,000 miles. The whole clearing the codes and not fixing anything is a slap across the face for a customer. Gm should be tearing people motors down to find out what the problem is. Or doing a few buybacks replaced with same exact truck and tear them down. Seems like customer service is not to high. I'm talking about all brands. I had trucks from other brands not start when the engine was full temp. Dealers would look at the trucks for hours and say yea it won't start for us also but we can't find out why. Ford wouldn't pay a penny to try to throw some parts to see if it fixed them problem. It was a work truck so I had to leave it running 12 hours a day. So I wouldn't get stranded. And had to fuel up with truck running, because they refused to pay a penny under warranty to replace parts.

Edited by Adamace1
Rhino83 Enthusiast

Rhino83

Posted
Posted

Did the ecm update per service bulletin received by dealership last Thursday. No issues as of yet but will see. I have found a few others on Facebook that have done the same.

msween313 Enthusiast

msween313

Posted
Posted
15 hours ago, Rhino83 said:

Did the ecm update per service bulletin received by dealership last Thursday. No issues as of yet but will see. I have found a few others on Facebook that have done the same.

They did the same exact thing for me and it took only 2 hours for the check engine light to come on again with the code of P0300.  Took it back to them and of course the light was off at this point and flickering.  The called me back and told me it was bad lifters which GM knows about.  Which I would hope so after reading all these forums.  They told me it could be 6-8 weeks until it can be fixed.  Only has 3,600 miles and this is the 4th time it has been in the shop for issues.  2021 GMC Sierra 1550 AT4 5.3 V8.

Rhino83 Enthusiast

Rhino83

Posted
Posted

Well one week and 2 days after doing the ecm update and the cel is back…guess I’m going back to the dealer for another round.

Rhino83 Enthusiast

Rhino83

Posted
Posted (edited)

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.

Edited by Rhino83

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

    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      www.enginelabs.com/news/what-i-learned-today-bearing-clearances-vs-oil-viscosities/     www.enginelabs.com/news/oil-viscosity-can-the-numbers-be-misleading/ The Big Lie… Coming full circle to the reason Lake discusses the Porsche engines in particular. Based on the 2000 samples in the SPEEDiagnostix database, increasing the oil viscosity in these engines, even those run on the track, showed no significant difference in results.   The smoking gun was in the oil chemistry. That is where the data shows higher instances of more wear. Molybdenum was the key; the higher the amount, the less the wear. Speed postulates that higher viscosity oils have more thickeners to artificially inflate their viscosity numbers. These thickeners lose viscosity under shear, and the result is that not all oils of the same viscosity have the same shear stability.   Having enough viscosity is the most important characteristic, but according to Speed, once that required viscosity level is reached, additive chemistry matters more than additional viscosity. Speed also states, oil pressure problems on the racetrack aren’t a viscosity problem; it’s an oiling system problem. Running a thicker oil is just a band-aid for an underlying oiling system problem.
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Can it still be Assembled II?   Viscosity on the decline by various means. Heat on the rise making that worse. Engine RPM in the tank. Smaller motors with more boost trying to emulate an electric motor. Full torque, zero rpm. Then we will triple the OCI. Argh.    But wait....there is more. LSPI has pushed a shift from Ca to Mg and as that cost more PLUS the run to lower sulfur compounds the TBN is moving in the wrong direction for the increased OCI's demanded.    That not being enough to placate a demand for a parameter they can't measure the other sulfur bearing compounds are also under attack. That would be zinc and phosphorus sulfonate compounds. To some degree those are being replaced with boron esters and others, i.e. titanium ect. All of which have shorter service lives. And there there is the "Secrete Sauce" marketing for AW adds that 'Can't be detected by UOA's" but trust me because I (the blenders) never ever lie.    Spoiler alert; ALL additives are sacrificial! Smaller amounts of the old blended with less robust versions of the new do not equal longer service lives. So what are the blenders recommending? Wait for it.......   MOVING THE GOAL POSTS! OMG      Let's declare the long standing TAN/TBN crossover irrelevant and tell people that soot is a great 'graphite' based lubricant which can aid tribo films. Wait, what? Let's declare that the standards used for oxidation and nitration were to conservative and can be expanded. Let's tell them that because GDI fuel dilution, although being a VISCOSITY KILLER and an acid generator is actually okay because we have better base oils that limit viscosity failure limits. (Said knowing this is measured in fractions of a centipoise and in bases not commonly used in shelf oils)   Lying from the heart is not just the new normal but we have a public, a very young public, that is so ignorant of the facts and so sure of their "RESEARCH" into AI driven models base in regurgitated  instead of scientific research based unvarnished, peer reviewed FACTS that the incoming guard is loosing their grip on reality and the OEM's are tickled pink while the blends bend the knee.    You have an ever limited set of tools to work with. And sooner or later those will be taken from you as the API and the EPA strangle the last remaining fluids from the system. What you have left is your wits. If you care to use them.    At some point in the very near future it will not longer be possible to do "What is best for the machine", and be replaced with "The best you have access too". You WILL be rewarded with half the life and twice the cost. That isn't that hard to predict.         
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      I trust you saw the other comment where he knew what he was talking about !. Yes, these darned newer vehicles with all their so smart they are stupid technology, goes and drains the battery down. As you might see my other comment, I installed a Noco 5 battery tender under the hood and at this point still have the cord routed so I have to lift the hood and then plug it in but am typically parked in a garage or a shed so its not risking the engine hood in the wind. That way I am assured or hopefully so of not finding I have a battery drawn down and can't even start the truck and that also damages the battery to draw it down too far. 
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      I guess no surprise my guesses were wrong !, at least now I know if I ever happen to see it grayed out in my own truck as to what is going on.    I never happened to catch my truck with it grayed out, it seemed every time I would test to see if there was an update it never found anything and yet more than once I would check to see if there was an update and there was nothing, then a day later or even that same morning I would drive to town and after more than one engine shut down in town as I did my errands it would pop up that there is an update now ready to install and the only place I have a connection to the internet is at home by wifi so its not as if it grabbed the download while driving. I don't trust these new vehicles due to all the crap they can decide to do while sitting for some days not running and run the battery down so most of the time if I know the truck will sit for a few days I plug in the battery tender I have mounted under the hood and so the only time the truck must have downloaded software was when it was sitting in the garage where the signal is awful but I have that tender plugged in and somehow it managed to download it. I honestly detest all this crap, way to easy to leave a person stranded.    Since I don't trust any of it I don't do the install of the already downloaded software until I get home and sometimes have even sat in the truck to watch what its doing as its going through the process to its conclusion as its not like it is set up that it will tell you the next time you fire up the engine that the update that was initialed actually installed or installed properly. Yes I can go into the updates and see the list. After I go through the install where I feel its safe to do so in case it breaks down as a result, I will plug in the battery tender after the fact to recharge as I don't know how much power its taking just to do the install and that can take a while for it to install. 
    • nfisherman
      Software Update

      By nfisherman · Posted

      Thanks for the reply. All settings were correct and the engine was off, as it was supposed to be. It turned out to be something simple. I took a drive for about an hour. I must have had a low battery without knowing it. The voltage gauge on the display looked ok. At the end of my drive, I shut off the engine and the update prompt came up and it updated normally. It’s ironic because one of the features of the update is a reduction of battery drain. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...