GM bulletin N232412720
What it saysService Update - Certain vehicles, with a 6.6L diesel engine, may have an Engine Control Module (ECM) that does not correctly provide all required data to emissions Inspection/Maintenance (I/M) testing stations. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Dec 6, 2023, received Dec 7, 2023, about the engine. It names 4 model years across Chevrolet and GMC (2024). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
One page for every brand it was filed under. Each brand’s bulletins: Chevrolet · GMC.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationPicked out of NHTSA’s summary below, word for word. The document itself is the record, and the dealer checks the VIN.
What it applies to, as NHTSA’s summary states it — build dates and equipment as the manufacturer filed them. The dealer checks the VIN and the build date on the door jamb; a vehicle outside the window is not covered by this bulletin.
Service Update - Certain vehicles, with a 6.6L diesel engine, may have an Engine Control Module (ECM) that does not correctly provide all required data to emissions Inspection/Maintenance (I/M) testing stations. Additionally, if the brake system control module would detect certain faults, the ECM may not properly illuminate the Malfunction Indicator Lamp (Check Engine Light). Dashboard warning messages and warning lights for traction control, stability control, and brake system remain functional for such faults. Dealers are to reprogram the ECM and TCM.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| N232412720 | Service bulletin | Dec 6, 2023 | 10246328 | PDF, 540 KB |
What the document itself lists
The manufacturer titles it “N232412720 – Service Update”.
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 9106854 | Sequential ECM/TCM Module Reprogramming with SPS | 0.7 hrs |
Read by machine from the document NHTSA serves (6 pages), read Sep 30, 2026. A part number is shown only where it matches GM’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.
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The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Doing the repair yourself, or pricing it before the shop does? Search the part by fitment on eBay Motors — the listing and the price are the seller’s.
Find the emission control for the 2024 Silverado 2500HD →Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.
Model years it names
Source: as the manufacturer filed themChevrolet 2 model years
GMC 2 model years
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 4 model years this bulletin names have filed 356 complaints with NHTSA since 2015. 163 of them name Electrical System, Engine — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
The contact owned a 2024 GMC Sierra 2500 HD. The contact stated that after parking the vehicle at night and plugging in the engine block heater to a standard 110-Volt outlet with an extension cord; 15-minutes later neighbors were screaming to the contact to exit the residence because the vehicle had caught on fire, and the residence was…
2024 GMC Sierra 2500HD · Engine · filed with NHTSA Nov 25, 2024 · ODI 11627201
The contact owns a 2024 GMC Sierra 3500. The contact stated while driving at approximately 60 MPH and towing a Forest River Riverstone Legacy 5th Wheel trailer, the brake pedal was depressed to slow for oncoming stopped traffic; however, the vehicle failed to respond as needed with the “Service Trailer Brake” warning light illuminated.
2024 GMC Sierra 3500HD · Electrical System · filed with NHTSA Jul 9, 2025 · ODI 11672342
The contact owns a 2024 Chevrolet Silverado 2500. The contact stated that while starting the vehicle, the check engine warning light illuminated. The vehicle was taken to the dealer, where the battery was disconnected temporarily to reset the ECM. The check engine warning light was reset; however, the failure reoccurred while driving.
2024 Chevrolet Silverado 2500HD · Engine · filed with NHTSA Nov 29, 2023 · ODI 11557393
In depth: 2024 Chevrolet Silverado 2500HD electrical problems →
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the engine
Source: same model, same component group89 other manufacturer communications filed against these GM models under the same component group (engine), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| N262572131-01 | Service campaign | Oct 23, 2026 | Customer Satisfaction Program. Certain vehicles listed above may have a condition in which the oil galley in the cylinder head was not dril… |
| N262572131 | Service campaign | Aug 28, 2026 | Customer Satisfaction Program. Certain vehicles listed above may have a condition in which the oil galley in the cylinder head was not dril… |
| 25-NA-339 | Service bulletin | Nov 6, 2025 | Under Field Actions N252494000, N252494001, the service procedure includes performing a PICO test on vehicle engines within the identified s… |
| 22-NA-080 | Service bulletin | Sep 6, 2025 | This technical bulletin provides a procedure to replace the camshaft actuator magnet to correct customer concerns of engine related shudder. |
| 25-NA-150 | Service bulletin | Jun 5, 2025 | This bulletin provides a procedure to check and replace the oil cooler seals before just replacing the oil cooler, for an oil leak. |
| 00-06-01-026R | Service bulletin | Jun 5, 2025 | This service bulletin provides information on replacing the intake manifold when the engine is replaced after severe internal engine damage. |
| 23-NA-170 | Service bulletin | May 16, 2025 | This bulletin advises the tech to inspect deeper into what may be the main cause of an engine failure. |
| 23-NA-153 | Service bulletin | May 15, 2025 | The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle response when the throttle plate is… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet and GMC, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM N232412720 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the N232412720 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every GM warranty extension on file lists the ones GM has filed.
Which vehicles does N232412720 cover?
The manufacturer filed it against 4 model years across 2 brands (Chevrolet and GMC): 2024 Chevrolet Silverado 2500HD, 2024 Chevrolet Silverado 3500HD, 2024 GMC Sierra 2500HD, 2024 GMC Sierra 3500HD. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.