GM service campaign N242450631
What it saysCertain vehicles equipped with a 2.7L engine (RPO L3B), may have an Engine Control Module (ECM) that does not sufficiently control fuel injector flow rate under certain driving conditions. NHTSA’s full summary ↓
GM filed this with NHTSA as a service campaign dated Sep 12, 2024, received Sep 18, 2024, about the engine. It names 12 model years across Chevrolet, GMC and Cadillac (2019–2023). A service campaign is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.
One page for every brand it was filed under. Each brand’s bulletins: Chevrolet · GMC · Cadillac.
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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 equipped with a 2.7L engine (RPO L3B), may have an Engine Control Module (ECM) that does not sufficiently control fuel injector flow rate under certain driving conditions. Dealers are to reprogram the ECM.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| N242450631 | Service campaign | Sep 12, 2024 | 11007868 | PDF, 259 KB |
What the document itself lists
The manufacturer titles it “N242450631 - Service Update”.
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 9107396 | Engine Control Module Reprogramming with SPS | 0.3 hrs |
Read by machine from the document NHTSA serves (5 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.
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.
Model years it names
Source: as the manufacturer filed themChevrolet 4 model years
GMC 4 model years
Cadillac 4 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 12 model years this bulletin names have filed 5,770 complaints with NHTSA since 2015. 2,712 of them name 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.
On the 2019 Chevrolet Silverado, the 143 owners who gave an odometer reading for Engine reported it at a median of 71,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
While driving on the highway my truck started to buck and had a loud engine knocking noise. Speed was greatly reduced so much so that I was going under 45 mph in a posted 65. The check engine light did not come on. While sitting on the side of the highway there was a severe engine knock only when the revs on the engine were increased.
2021 GMC Sierra · Engine · filed with NHTSA Sep 9, 2021 · ODI 11432369
i FEEL IT IS IN THE FUEL MANAGEMENT SYSTEM When driving along every now and then you can feel a vibration like diving on rumble strips. there is no rhyme or reason for it. I had it to the dealer and they told me that was normal, if you don't want it to do it then drive in 9th gear. I'm not going to shift to 9th every time I drive
2022 GMC Sierra · Engine · filed with NHTSA Jan 3, 2023 · ODI 11499958
The contact owned a 2020 GMC Sierra Denali. The contact stated that while the vehicle was parked, there was an abnormal knocking sound coming from the engine compartment. The check engine warning light was intermittently illuminated. The vehicle was taken to a dealer; however, the cause of the failure was not yet determined.
2020 GMC Sierra · Engine · filed with NHTSA Sep 11, 2026 · ODI 11763621
In depth: 2022 Chevrolet Silverado engine problems → · 2021 Chevrolet Silverado engine problems → · 2020 Chevrolet Silverado engine problems → · 2019 Chevrolet Silverado engine 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 group188 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 |
|---|---|---|---|
| N262576260 | Service campaign | Oct 15, 2026 | General Motors has decided to conduct a Voluntary Emission Recall. Certain vehicles may have a condition that could cause a small exhaust le… |
| N262568830 | Service campaign | Aug 4, 2026 | Certain vehicles listed above may have a condition in which the oil filter was not adequately tightened. Dealers are to check and tighten th… |
| N262552610 | Service campaign | May 7, 2026 | Certain vehicles may have a condition that could cause the crankcase pressure sensor to fail. If this failure occurs, the Malfunction Indic… |
| N262548050 | Service campaign | Apr 24, 2026 | Certain vehicles, may have a condition that could cause the Catalytic Converter to fail. If this failure occurs, the Malfunction Indicator L… |
| N252494003-02 | Service campaign | Jan 21, 2026 | Certain vehicles listed above, may have a condition where the connecting rod and/or crankshaft engine components in these vehicles may have… |
| 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… |
| N252508341 | Service campaign | Sep 16, 2025 | Certain vehicles listed above, may have a condition that could cause the engine coolant control valve to fail an onboard vehicle diagnostic… |
| N252508340 | Service campaign | Sep 16, 2025 | Certain vehicles may have a condition that could cause the engine coolant control valve to fail. If this condition were to occur, the Malfun… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet, GMC and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM N242450631 a recall?
No. A service campaign 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 N242450631 repair free?
A service campaign is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.
Which vehicles does N242450631 cover?
The manufacturer filed it against 12 model years across 3 brands (Chevrolet, GMC and Cadillac): 2023 Cadillac CT4, 2022 Cadillac CT4, 2021 Cadillac CT4, 2020 Cadillac CT4, 2022 Chevrolet Silverado, 2021 Chevrolet Silverado and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.