GM bulletin N232430460
What it saysCertain vehicles may have a condition that could cause the engineâs cylinder 2 glow plug to fail. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Jan 29, 2024, about the engine. It names 2 model years across Chevrolet and GMC (2020). 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.
Special Coverage. Certain vehicles may have a condition that could cause the engineâs cylinder 2 glow plug to fail. If this condition occurs, the Malfunction Indicator Lamp (Check Engine Light) will illuminate, and a diagnostic trouble code will set. Dealers are to replace the cylinder 2 glow plug as necessary. The repairs will be made at no charge to the customer.
Trouble codes it names: P0672 P06C6 P1339 all 3 read from the document itself; NHTSA’s summary names none
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| N232430460 | Service bulletin | Jan 29, 2024 | 10249404 | PDF, 221 KB |
What the document itself lists
The manufacturer titles it “N232430460 - Special Coverage”.
Labour operations and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 9900876 | Glow Plug Replacement Add: Diagnosis Time | 0.7 hrs |
| 9900878 | Customer Reimbursement Denied – For USA dealers only N/A ZREG ** For USA and Canada… | 20 hrs |
Read by machine from the document NHTSA serves (4 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.
Model years it names
Source: as the manufacturer filed themChevrolet 1 model year
GMC 1 model year
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 2 model years this bulletin names have filed 1,246 complaints with NHTSA since 2015. 551 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 2020 Chevrolet Silverado, the 80 owners who gave an odometer reading for Engine reported it at a median of 68,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
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
At cold start up, the truck immediately illuminated the check engine light with a message of reduced engine power. A shut down and restart produced the same results. Shut the truck off and pulled the trouble code P26BB. Next start up, check engine light was still on, but the reduced engine power message was gone.
2020 Chevrolet Silverado · Engine · filed with NHTSA May 5, 2020 · ODI 11323321
In depth: 2020 Chevrolet Silverado engine problems → · 2020 GMC Sierra 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 group162 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… |
| 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… |
| 24-NA-241 | Service bulletin | Sep 6, 2025 | This informational bulletin advises the technician of a part number change for long block engines used in the trucks noted. |
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 N232430460 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 N232430460 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 N232430460 cover?
The manufacturer filed it against 2 model years across 2 brands (Chevrolet and GMC): 2020 Chevrolet Silverado, 2020 GMC Sierra. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.