Repeat Check Engine Light Issues - 2021 5.3 1500 w/ 10 Speed

tjonesdfw · May 13, 2022

Truck is a 2021 1500 with the 5.3 and 10 speed. Was purchased new and has been to the dealer 5 times in 12K miles for check engine light issues.

1. First time it flashed for less than a minute and went off without any drivability issues. Dealer scanned and found misfire code on 1 & 6, said no fix from GM yet and sent me on my way.

2. Second time, same light scenario but truck briefly ran rough. Dealer scanned and found misfire code on 1 & 6, did the crankshaft position re-learn.

3. Third time, happened again just like before less than a week later. Dealer said no other fix was available from GM yet, and to just drive it until they notified me.

4. Fourth time, happened again just like before but several months later. Dealer performed a TSB out to relocate one of the harnesses in engine bay away from a heat source.

5. Fifth time, CEL flashed for 60 seconds, went solid for 30, then flashed again, and finally went solid and stayed solid. Truck bucked and surged despite giving it steady throttle, and wouldn't make it up the on-ramp without putting it nearly on the floor. Once on the highway it finally smoothed out, but the light stayed lit. On-Star notified me to "service emissions system within 7 days." Sat at the dealer for almost week. They claim to have checked to see if it was lifters, but performed TSB #21-NA-154 AGAIN, claiming that they have different software available now, from the first time they re-learned the crankshaft position sensor (see Item 2 above). Told me they have three '21s in their shop all for failed lifters right now, and they "hoped" this fixed mine. I argued that #21-NA-154 specifically says its only for check engine light issues WITHOUT drivability issues and I DID have major drivability issues, but they insisted their tech said this would fix mine despite having major drivability issues this time.

Anyone else experiencing this many CEL issues? I feel like they're just re-setting the light every 2K miles and sending me on my way without any real fix. Thanks

Steve-2019 · May 13, 2022

1 hour ago, tjonesdfw said:

Truck is a 2021 1500 with the 5.3 and 10 speed. Was purchased new and has been to the dealer 5 times in 12K miles for check engine light issues.

1. First time it flashed for less than a minute and went off without any drivability issues. Dealer scanned and found misfire code on 1 & 6, said no fix from GM yet and sent me on my way.

2. Second time, same light scenario but truck briefly ran rough. Dealer scanned and found misfire code on 1 & 6, did the crankshaft position re-learn.

3. Third time, happened again just like before less than a week later. Dealer said no other fix was available from GM yet, and to just drive it until they notified me.

4. Fourth time, happened again just like before but several months later. Dealer performed a TSB out to relocate one of the harnesses in engine bay away from a heat source.

5. Fifth time, CEL flashed for 60 seconds, went solid for 30, then flashed again, and finally went solid and stayed solid. Truck bucked and surged despite giving it steady throttle, and wouldn't make it up the on-ramp without putting it nearly on the floor. Once on the highway it finally smoothed out, but the light stayed lit. On-Star notified me to "service emissions system within 7 days." Sat at the dealer for almost week. They claim to have checked to see if it was lifters, but performed TSB #21-NA-154 AGAIN, claiming that they have different software available now, from the first time they re-learned the crankshaft position sensor (see Item 2 above). Told me they have three '21s in their shop all for failed lifters right now, and they "hoped" this fixed mine. I argued that #21-NA-154 specifically says its only for check engine light issues WITHOUT drivability issues and I DID have major drivability issues, but they insisted their tech said this would fix mine despite having major drivability issues this time.

Anyone else experiencing this many CEL issues? I feel like they're just re-setting the light every 2K miles and sending me on my way without any real fix. Thanks

So did they preform the "new" TSB and if so, how is it now?

tjonesdfw · May 13, 2022

Yes, they did the supposedly "new" TSB, despite the TSB being dated last year before they did it the first time. Low and behold the CEL is off again like it usually is and things are running smoothly... for now. Just seems like every 2K miles it rears its head again and each time it does, it gets progressively worse.

kmeleon · May 14, 2022

I had issues that sound very much like yours but without the drivability issues back from 2/21 till almost 11/21. They finally fixed it with an updated tune but it took a long time to get to that point. But the drivability issues you're mentioning are definetely something different. May be a lifter intermittently going out but everytime I read of someone with that it's a permanent issue, not sporadic.

tjonesdfw · May 14, 2022

Which update did they do that finally fixed yours? Glad to know they were finally able to resolve it. I love the truck otherwise, and a ‘22 is nearly 10k more for the same truck vs what I paid.

voided3 · May 14, 2022

Our '21 Silverado with the L84 5.3 had the flashing CEL come on four times due to failing lifters on cylinder #6 and #8, though the misfire codes were only coming from cylinder #8. After replacing the lifters, the issue hasn't come back.

kmeleon · May 19, 2022

On 5/14/2022 at 2:30 PM, tjonesdfw said:

Which update did they do that finally fixed yours? Glad to know they were finally able to resolve it. I love the truck otherwise, and a ‘22 is nearly 10k more for the same truck vs what I paid.

I don't recall the exact update but I do know it came out in late Sept 2021.