2024 LZ0 ECM CALIBRATION UPDATE

NMTRUCKER

NMTRUCKER

Well-known member
For anyone who has a 2024 Silverado or Sierra with the LZ0, GM has just issued a Technical Service Bulletin (TSB 24-NA-094) for an ECM update. This covers Diagnostic Trouble Codes; P049D, P11D5, P138C, P1428, P2002, P20FE, P2297, P22FE, P22FB, P2463, and P2459. Again this is for model year 2024 only. Hope this helps.
 
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I'm not throwing any codes at the moment but I did have a P2297 a while back. The CEL I got at the same time cleared itself and the dealer told me they didn't have a TSB for P2297, so I should just ignore it. That was a couple of months ago and i haven't gotten any more CEL's, so I haven't thought mmuch about it. I am curious to see if this TSB improves time between regens. I'll be taking the truck to the dealer soon for the complimentary oil change, I'll ask about the TSB when I do.
 
chaseydog said:
I'm not throwing any codes at the moment but I did have a P2297 a while back. The CEL I got at the same time cleared itself and the dealer told me they didn't have a TSB for P2297, so I should just ignore it. That was a couple of months ago and i haven't gotten any more CEL's, so I haven't thought mmuch about it. I am curious to see if this TSB improves time between regens. I'll be taking the truck to the dealer soon for the complimentary oil change, I'll ask about the TSB when I do.
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This TSB was released on the 30th of May FYI.
 
NMTRUCKER said:
This TSB was released on the 30th of May FYI.
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It's Saturday and I'm at the dealership for the complimentary oil change. I brought up the TSB, but the Service Advisor told me since I'm not currently throwing any codes, they normally would not perform the TSB. He told me I could bring my truck back in during the week if I wanted it checked out, but I'll hold off for now.
 
chaseydog said:
It's Saturday and I'm at the dealership for the complimentary oil change. I brought up the TSB, but the Service Advisor told me since I'm not currently throwing any codes, they normally would not perform the TSB. He told me I could bring my truck back in during the week if I wanted it checked out, but I'll hold off for now.
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Your P2297 should still be resident in the ECM (maybe as a pending code). I had a similar thing happen with my 2023 GMC LZ0. I had a CEL come on and then on the way to the dealership it went off. The service advisor at first said I would have to pay for the GM TSB software update because I didn’t have an active CEL. He changed his mind after the tech did the update. I’ve never owned an OBD2 scanner but I’m really tempted to get one. Good luck with your truck.
 
NMTRUCKER said:
Your P2297 should still be resident in the ECM (maybe as a pending code). I had a similar thing happen with my 2023 GMC LZ0. I had a CEL come on and then on the way to the dealership it went off. The service advisor at first said I would have to pay for the GM TSB software update because I didn’t have an active CEL. He changed his mind after the tech did the update. I’ve never owned an OBD2 scanner but I’m really tempted to get one. Good luck with your truck.
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I cleared the code with the Banks iDash. It's possible that the dealer might still be able to pull it up, but as I don't have a CEL I don't see an immediate need for the TSB. That may change if the update proves to increse time between regens.
 
chaseydog said:
I cleared the code with the Banks iDash. It's possible that the dealer might still be able to pull it up, but as I don't have a CEL I don't see an immediate need for the TSB. That may change if the update proves to increse time between regens.
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A few days ago I updated my IDASH with the latest firmware (5-1-24-11). Haven’t driven my truck since the install and I’ll have to check out the “clear codes” feature.
 
4500 miles later, and I've got my second CEL once again for P2297. Looks like I'll head back to the dealer. Now that I'm throwing a code, I'm going to get them to update the ECM per TSB 24-NA-094.
 
Once again the CEL has already cleared itself. I'll call the dealer Monday morning to see if theres any point in bringing the truck in. The GM app is still showing an emissions fault, though I haven't noticed any loss of performance or mpg.
 
chaseydog said:
Once again the CEL has already cleared itself. I'll call the dealer Monday morning to see if theres any point in bringing the truck in. The GM app is still showing an emissions fault, though I haven't noticed any loss of performance or mpg.
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I would press them to perform the software update especially since this is the second occurrence. I had a different CEL that disappeared just before I arrived at the dealership and they said initially that I would have to pay for their TSB related software update. However, after a bit of casual whining they agreed to pay. I think it was like $168 for a half hour of tech time. I did get to spend time in their waiting room and intermittently watched about 7 sales folks twiddling their thumbs.
 
CEL was back on Saturday morning but once again cleared itself later in the day. It's now Monday morning and the CEL has not come back on. I called the dealer and asked if there was any point in bringing the truck in. They told me that they could let me know what code is in memory, which I already know, but if the CEL is not on they won’t do a repair.

I canceled the appointment. I cleared the code with the Banks iDash but the Emissions Trouble is still showing in the app. I'm hoping that will clear as well after driving around for a while.
 
CEL was back again yesterday. Brought it into the dealer this afternoon and they updated the ECM. After updating the ECM everything tested out good so no need to change out any sensors.
 
As an interesting aside the dealer told me the trouble shooting and reapair would take 4 - 5 hours, offered me a ride back to work, and introduced me to Willie, their driver. Super nice old guy, told me all about planting tomatoes and how one of his neighbors had shot out the drivers side window of his truck. Unfortunately Willie wasn't available latter that day to take me back to the dealer to get my truck. I ended up in an Uber being driven by an Eastern European woman who drove like we had the KGB on our tail. Interesting day. Wonder if they're the ones that shot out Willies window.
 
Not quite a week yet since the dealer updated the ECM. Thankfully no more CEL's to report but I am having a problem with the myGMC app. The app is still showing an emissions issue. It's also been reporting my fuel level at 32% for the last two weeks, despite the tank having been topped of durring that time. According to the DIC I'm currently at half a tank. I can still use the app to remote start and lock the doors, but the truck status info will not update.

I bought the app issue up with the dealer when I had the ECM updated and was told the app should update within 24 hrs. I called them back after that didn’t happen and was told they don't have access to the app and I'd need to call OnStar.

My OnStar premium is expired but I still have Remote Start and Connected Services. I was expecting OnStar to subject me to a sales pitch prior to connecting me to troubleshooting but to my surprise they did not and the service team has been helpful and friendly. Initially we didn’t do much more than reinstall the app which did not solve the issue. I was told my issue would be escalated.

I received a call the next day. We did another reinstall and then a power cycle, neither of which solved the issue. Once again I was told my issue would need to be escalated, which according to the rep I spoke to may take 5 - 7 days before I hear back from them. Hoping to have this resolved in the coming week. I'll update when I know more.
 
I just took delivery last week of a 3.0 Siliverado that was manufactured about June 15 in the Silao plant . I wonder if the update flowed out to the production line by then? One would think the updates would be done before leaving the plant.
 
Andy said:
I just took delivery last week of a 3.0 Siliverado that was manufactured about June 15 in the Silao plant . I wonder if the update flowed out to the production line by then? One would think the updates would be done before leaving the plant.
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This TSB was issued in May 2024 so I would assume this update was made to your vehicle before it left the plant.
 
Its been more than a week and no call from OnStar tech support so I called them. The tech had me go through the same troubleshooting steps, sign in and out of the app, delete and reinstall the app, all to no avail. He told me he kicking it back up the chain and I should hear from them in 3 to 5 days.
 
chaseydog said:
Its been more than a week and no call from OnStar tech support so I called them. The tech had me go through the same troubleshooting steps, sign in and out of the app, delete and reinstall the app, all to no avail. He told me he kicking it back up the chain and I should hear from them in 3 to 5 days.
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Inch by inch, step by step up the tech chain we go. Why would it take 3-5 days for a response? But don’t be 3-5 days late paying your bill or they’ll send out the goon squad to bust some heads. Anyway, best of luck getting this issue resolved. 🤞
 
NMTRUCKER said:
Inch by inch, step by step up the tech chain we go. Why would it take 3-5 days for a response? But don’t be 3-5 days late paying your bill or they’ll send out the goon squad to bust some heads. Anyway, best of luck getting this issue resolved. 🤞
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For a business that sells itself on a prompt response if I get into an accident or my truck is stolen thier response time is disappointing.
 
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