Check engine light

[SDMike]

I took my 19’ AT4 in for repair 2 days after I bought it because the check engine light came on with 150 miles on it. They found nothing wrong, so I picked it up. 2 days later, the check engine light came on with 217 miles on it. Took it in again and they receive a code that the auto start/stop control module had a voltage reading that triggered the code. They replaced the module. I drove it for a few more days and the check engine light came on again with 300 (ish) miles on it. I drove it until my appointment a few days later and the light never shut off. The day of my appointment, the check engine light shut off. The Dealership tech called a corporate GM tech and was told to take out fuses 52 & 53 because those control the auto start/stop technology. When they removed the fuses, the truck wouldn’t start at all. They removed to fuse block and found that it was the wrong part number, thus the wrong fuse block. Of course GM is on strike, so they can’t get the new block in due to shipping issues. They say that everything else should work fine, but I don’t trust “should”. Anyone else have similar issues with the auto start/stop or a check engine light?

Edited October 21, 2019 by SDMike

[BrettC]

Had a light come on my '20 SLT with 300 miles on it today. Went off before I could have it scanned at Auto Zone. Keeping an eye on it (and this thread now!)

[davester]

Even if the light goes out, you can still go and get the codes read to see what happened.

[BrettC]

51 minutes ago, davester said:

Even if the light goes out, you can still go and get the codes read to see what happened.

That's what I thought! Had two different Auto Zones tell me otherwise unfortunately...

[davester]

So, they wouldn't hook up their reader to your vehicle, or they did and said there were no codes in the history?

 

I know my truck will store codes for all kinds of stuff, even after I fix the problem.

[BrettC]

Didn't even hook it up. I can only assume there is a log or history of some sort given the amount of technology in vehicles these days - maybe their readers just don't have that functionality?

[davester]

No, even the most basic code readers can get history codes from the engine computer.  And there can be current codes, even if the CEL is off...

Edited October 30, 2019 by davester

[rich1464]

I am having this issue now. 8 trips to the dealer 4 replacement parts. GM tech is flying out to look into this. 

[nichos]

I had a similar issue. I was unable to remote-start my truck, when I got in I had a "check engine light" on. It stayed on for about 3 or 4 starts.

Took it to the dealer a few days later and he said he was able to see the light came on, and it was a "communication error." He had no idea what that meant though

He did say all he can do is keep it here until it reproduces again. I haven't seen it since, been about a month now.

[Ae23]

I have a ‘20 at4 with 1000 miles CEL just came on...??? Anyone ever get any solid response from GM? I plan on stopping by the dealer and seeing what they say tomorrow. 

[Kuno Ojeda]

same thing happen to me, I remote started my 2020 sierra at4 with 486 miles and when i got on the check engine light was on. after work I didn't use remote start and light was gone?? it makes me mad! brand new truck and a engine light on?? wtf.

[Kuno Ojeda]

On 5/13/2020 at 7:10 PM, Ae23 said:

I have a ‘20 at4 with 1000 miles CEL just came on...??? Anyone ever get any solid response from GM? I plan on stopping by the dealer and seeing what they say tomorrow. 

you light still one? let me  know what you hear from dealer. Ty

[Ae23]

Light is still on, didn’t make it to the dealer on Friday... it’s on the plan for Monday. I will pass in the response from the dealer. 

[bcalaway]

I purchased a 2020 AT4 6.2L.  Check engine light came on at 40 miles - went away after shutting it off and starting it.  Fast forward 6 days - I have 350 miles on it and am NOT at home.  Go to get into the truck after leaving 'fob' in the truck over night.  The dash tells me "FOB Identified" or whatever the heck it says, and when I go to start my rig after it sitting for a day, I lose ALL power to the truck.  Windows won't roll down, lights won't turn on - completely DEAD.  I took the keyfob and stepped out of the rig trying to unlock/lock and even remote start and NOTHING. 

 

I asked a family member to give me a jump (thankful I was around other people - had I been in the woods I'd be screwed) after 3-4 minutes with cables on, the truck fires up and check engine light is on.   After 15 minutes I shut the truck off and fired it right back up.  Battery levels were fine - everything checked out except for the check engine light not going off.  Drove it 140 miles home and it drove fine - until I took cruise control off and was heading home off the freeway, and it seemed to be "skipping/lunging" at low speeds, almost felt like a misfire/bad fuel or something.  I called the dealership and took it in - they've had it for 1 week now and they claim the light came on due to a transmission code.  I haven't heard BOO from them, but super frustrating that I spent as much as a did to have a truck that I don't have to drive now.....

[CrimeFactory]

Bought a 2020 GMC 1500 Denali, had issue with the Auto/stop about 5 days after driving it home. Pulled up to a stale red light and I took my foot off the brake the engine was mid auto stop and it went into what felt like convulsions for about 15 seconds in the intersection, almost stalled out but slowly pulled it together and continued driving. ( no check engine light ).  I now try to remember to turn off the auto stop every time I get into the truck, which is somewhat annoying to begin with. Truck has a weird idle at stop, not sure if that's typical of the 6.2 I've only had 5.3s previously. now 4000km I make an appointment for oil change and to have them investigate the auto stop incident, started the truck this morning and check engine light is on.. Changed my appointment to tmw and will have to see what happens. I could tell in the first week of driving this truck it will be prone to auto stop and battery problems, I do have extended warranty but will have to check if auto stop components are covered past 3 yr which I suspect they are not.