Brand new Sierra 5.3 CEL flashing

Michael Ruch · May 31, 2020

I just find it very weird that 3600 no problems at all then I got the oil changed on weds this week and Friday this all started to happen.

Where or how do you think over filling the oil causes the miss?

thanks!

Andyh1 · May 31, 2020

I just find it very weird that 3600 no problems at all then I got the oil changed on weds this week and Friday this all started to happen.

Where or how do you think over filling the oil causes the miss?

thanks!

I would have to look it up, I read it somewhere. But you kkow how it goes when you dive into forums, so much unfounded information.

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jnissen · May 31, 2020

Interested what the oil level turns out like.

BTW nice hens.

Nightwatch89 · June 2, 2020

My 2020 Silverado just did this on the way home from my parents house. I bought the north sky blue lt 1500 because the shadow grey did this on a test drive. I don’t think it’s isolated. I’ve also got the 5.3. Taking it in tomorrow for them to look at.

Andyh1 · June 3, 2020

My 2020 Silverado just did this on the way home from my parents house. I bought the north sky blue lt 1500 because the shadow grey did this on a test drive. I don’t think it’s isolated. I’ve also got the 5.3. Taking it in tomorrow for them to look at.

Ok let's start documenting this situation. Good luck tomorrow

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Jetblackz28 · June 3, 2020

So I just had a similar issue. Was driving and then my CEL started to flash and then my dash said to get the Parking Brake Serviced and the ESC(?) System Serviced, after a minute or so everything went back to normal and all lights went off. Took it to the dealership later that week and all they could see was a misfire code. They stated everything looked good and all the computers in the truck were running the most up to date software. And they couldn't get the truck to duplicate the problem. They told me they called GM HQ to see if there was any new/unreleased info on the truck, but there wasn't.

I have a 2020 Silverado LT All-Star Edition, 5.3 with 8 speed and just over 5k miles.

Nightwatch89 · June 3, 2020

I’ve got the same trim. Same package. At the shop now, so I’ll see what they say. I doubt they’ll have a magic answer, haha. Might just be a waiting game for either a recall or some sort of software update.

Jetblackz28 · June 3, 2020

22 minutes ago, Nightwatch89 said:

I’ve got the same trim. Same package. At the shop now, so I’ll see what they say. I doubt they’ll have a magic answer, haha. Might just be a waiting game for either a recall or some sort of software update.

Yeah unless it happens when they have it in hand they won't be able to tell much. I asked why it showed servicing those systems if it was just a misfire that prompted the CEL to flash. They said it was probably a power/voltage surge through the system that just accidentally triggered some sensors.

Nightwatch89 · June 3, 2020

Got it back and as I suspected, no answers. They saw a history of misfires on cyl 1,4,5,6 and 7. They couldn’t duplicate the issue and found nothing wrong on their inspection. The saga continues until it happens again. Fingers crossed.

hendooman · June 3, 2020

Parking Brake Serviced and the ESC(?) System Serviced...right at 5K on mine and the same thing just happened. Parking brake and ESC, was on for maybe 10 seconds and then went off. Oil change in the next couple days.

Andyh1 · June 9, 2020

Update: 1800 miles and today the darn CEL came on... This time it did not flash as in my original post (scroll up) but stayed on for 30 miles on my drive home.

Dealer tomorrow for a second time. [emoji35] Starting to get annoyed.

I purchased a scanner today because I have a feeling that this truck is gonna be a bit more high maintenence than my BMW's

Edit: check engine light went away this morning. This is so strange.

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SAVA6E · February 23, 2021

OP- did anything come of this? I experienced the same issue in my 2020. CEL flashing on two separate occasions and P0300 codes at the dealer but no other issues found.

kmeleon · February 24, 2021

I posted this to the P0300 topic in the main forum as well. Here's a copy and paste of my message. I'm starting to see a trend here.

Just had this happen to me again this morning. Last time was at 1300 miles on the clock. 2021 GMC Sierra Elevation w/5.3L

At 1300 miles is started flashing the CEL under light acceleration at about 20-25mph... let off the gas and the light went out... hit the gas lightly again light started flashing again, pulled over and turned the truck off. Started the truck, drove off and no issue from there. I took it to the local dealer West of me and they hooked it up to the Tech2 and found P0300 (generic misfire) but that usually will be accompanied by a p0301-p0308 to call out the cylinder that misfired. No such luck. So they sent me on my way and I didn't have another light until today.

Fast forward to today (2050 miles on the truck), remote started the truck for warm up and left about 15 minutes later from my house. I got a couple 1000 ft and the CEL is flashing, doesn't matter on the gas, off the gas...it's flashing. So I pulled over and shut the truck off. Start the truck, no issues going to work.

Luckily I have an appt tomorrow (at a dealer East of me this time, wasn't thrilled with the lack of effort on the West dealer's part) for my On-star/Sirius unavailable message that pops on my screen every time I start it up. Oh, and my drivers side temperature readout on the climate knob has a bad segment that won't display for about 10 seconds until it warms up a bit.

This is getting old.

kmeleon · February 26, 2021

So the dealer found p0300, p0301 and p0306. So misfires on cylinder 1 and 6, about 22 of them to be exact. They're blaming it on old gas/covid, blah blah. They told me to use toptiergas.com to find a station that GM recommends....Costco is on there as a recommended filling station in my area....it's the only gas I've put in this truck so far.

So I'll continue to report on here and to the dealer if it misfires, I finally ordered a new OBD code reader because I forgot to pull the old one out of the 07 Avalanche when I sold it. So at least I'll be able to read the codes and keep track if they happen to pop again.

Disappointing.

Edited February 26, 2021 by kmeleon

Z71TrailBoss · February 26, 2021

So the dealer found p0300, p0301 and p0306. So misfires on cylinder 1 and 6, about 22 of them to be exact. They're blaming it on old gas/covid, blah blah. They told me to use toptiergas.com to find a station that GM recommends....Costco is on there as a recommended filling station in my area....it's the only gas I've put in this truck so far.

So I'll continue to report on here and to the dealer if it misfires, I finally ordered a new OBD code reader because I forgot to pull the old one out of the 07 Avalanche when I sold it. So at least I'll be able to read the codes and keep track if they happen to pop again.

Disappointing.

My 2021 Trail Boss with a 5.3L 10 speed auto with 3,500 miles is at the local dealer for the second time with this problem. Which code reader are you going with?

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