Check engine light

RadoPhan · June 5, 2020

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.

I’ve gotten used to the autostop function and it hasn’t been an issue for me. If you really want to get rid of it without pressing the button every time you start your truck, try this. It’s supposed to remember your last on/off option and save it from resetting back every time you turn your truck back on.

https://www.autostopeliminator.com

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Ae23 · June 5, 2020

That seems like an easy install and a quick fix... any know issues with warranty? Is it something to remove before going in for warranty work or servicing? If the tech plugs into the truck can they detect that something is not right with the auto start stop function?

RadoPhan · June 5, 2020

That seems like an easy install and a quick fix... any know issues with warranty? Is it something to remove before going in for warranty work or servicing? If the tech plugs into the truck can they detect that something is not right with the auto start stop function?

I don’t think it does but this is from their FAQs in the site.

“While we don't have control over your warranty, we haven't had a single report of a warranty related issue. For the most part, the dealership folks hate start/stop too so it's unlikely they'll give you any trouble. If you're worried, the device can easily be removed before taking it to the dealer. For most dealer visits the removal is unnecessary unless you're having a start/stop issue or an issue with the infotainment. In that case, it's probably easier to remove it then to take the chance of a service manager being difficult. When in doubt, you can always check with the service manager beforehand. That'll give you the best read on where they stand.”

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snay502 · June 8, 2020

2019 5.3 Silverado - check engine light came on randomly. Put a K and N cold air intake on it and a flowmaster super 40 muffler recently. Any connection?

RadoPhan · June 8, 2020

2019 5.3 Silverado - check engine light came on randomly. Put a K and N cold air intake on it and a flowmaster super 40 muffler recently. Any connection?

I have an AFE intake and Borla muffler and for awhile nothing came on. Then suddenly my light came on after a remote start. Had a friend that experienced the same thing from a remote start. I disconnected the battery for 10 minutes and restarted and it was still on but then cycled a stop, lock the car and then unlock and start then it was gone. Truck drove fine during the whole time the light was on so I’m pretty sure nothing was wrong.

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snay502 · June 8, 2020

This was in fact after a remote start. I have driven the truck multiple times after the mods - with no light.

Must be connected to the remote start. I'll start it non remotely and see if the light

stays on. Then I'll try unhooking the battery and the unlock / start method.

The truck is running just fine, the light is annoying. Thanks!

Shanks · June 11, 2020

just bought a 2020 Sierra AT4 5.3. 2nd day...with on 100 miles on it, check engine light comes on. have an appt tomorrow to check it out. I also turn off the auto stop/start, so it has yet to be utilized.

jlong1984 · June 14, 2020

Welp, add me to the list. 2019 Sierra SLT 5.3/8-speed 15,000 miles. I came out of the grocery store and the check engine light stayed on solid. No issues with drivability. Voltage, temp and oil pressure all read fine. I drove the truck around all morning and didn't have any issues. I did fill up with gas in the morning, so that could be a potential cause.

This is the first problem I've had with the truck, hopefully it's nothing major. I'll report back whenever the dealer can get a chance to look at it.

Mikedfw · June 14, 2020

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.

Have the 6.2, no weird idle for me at all. I've occasionally had a weird clunk when stopping that is the only thing abnormal I've experienced with the drivetrain and it doesn't happen that often.

As for auto stop, I hated turning it off at first, but now it's a habit, first thing I do when I start the vehicle and I dont even notice anymore its second nature, just give it time to get used to doing it.

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Sunny82 · June 15, 2020

15 hours ago, jlong1984 said:

Welp, add me to the list. 2019 Sierra SLT 5.3/8-speed 15,000 miles. I came out of the grocery store and the check engine light stayed on solid. No issues with drivability. Voltage, temp and oil pressure all read fine. I drove the truck around all morning and didn't have any issues. I did fill up with gas in the morning, so that could be a potential cause.

This is the first problem I've had with the truck, hopefully it's nothing major. I'll report back whenever the dealer can get a chance to look at it.

Same exact thing for me! 2019 Sierra SLT - 5.3 / 8 speed and 12.7K miles. Normal driving into this past weekend, then yesterday...CEL on with no drivability issues. I had not got gas in a week, but thought about the same thing with the "lose cap issue" on older models. I'm going to give it a few days, get codes pulled and then contact dealer if it stays on. *** mine is not related to a remote start.

jlong1984 · June 16, 2020

On 6/15/2020 at 9:36 AM, Sunny82 said:

Same exact thing for me! 2019 Sierra SLT - 5.3 / 8 speed and 12.7K miles. Normal driving into this past weekend, then yesterday...CEL on with no drivability issues. I had not got gas in a week, but thought about the same thing with the "lose cap issue" on older models. I'm going to give it a few days, get codes pulled and then contact dealer if it stays on. *** mine is not related to a remote start.

Mine went off after driving around yesterday. I'm still taking the truck in later this week to see if they can pull the stored codes and just to document the issue in case further issues arise.

Sunny82 · June 16, 2020

7 minutes ago, jlong1984 said:

Mine went off after driving around yesterday. I'm still taking the truck in later this week to see if they can pull the stored codes and just to document the issue in case further issues arise.

Wow....I cranked mine yesterday after 30+ hours of not driving and it was off too. I drove 4 different times yesterday and it remained off. Please post what the dealer says the codes are. Im going to wait to see if it comes back on before I go to the dealer. Thanks!

jlong1984 · June 17, 2020

On 6/16/2020 at 10:46 AM, Sunny82 said:

Wow....I cranked mine yesterday after 30+ hours of not driving and it was off too. I drove 4 different times yesterday and it remained off. Please post what the dealer says the codes are. Im going to wait to see if it comes back on before I go to the dealer. Thanks!

Mine ended up having to do with a loss of communication from the brake module. That's what the dealer said at least. They said they have been seeing this issue pop up recently in other trucks as well. They ended up reprogramming something, hopefully they were shooting me straight.

CrimeFactory · June 18, 2020

9 hours ago, jlong1984 said:

Mine ended up having to do with a loss of communication from the brake module. That's what the dealer said at least. They said they have been seeing this issue pop up recently in other trucks as well. They ended up reprogramming something, hopefully they were shooting me straight.

Yup same here! Told me that GMC is aware of the problem and they have engineers working on it. Ive had mine come on twice already and they said if it comes on again they will need gmc to send out an engineer to investigate because it will be an Active Case

Aaron G · May 30, 2021

I got a 2018 gmc sierra and noticed when I turn the ignition on engine light stays on without the truck running but when it’s on engine light is not on is that normal???