GM bulletin 23-NA-043
What it saysThis service bulletin provides a procedure to replace the valve lifter and guides to correct customer concerns of Poor Engine Performance, Engine Misfires, Malfunction Indicator Lamp (MIL) Illuminated - DTC P0300… NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Feb 26, 2024, received May 6, 2023, about the engine — 3 documents under this number. It names 8 model years across Chevrolet, GMC and Cadillac (2020–2021). 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 · Cadillac.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis service bulletin provides a procedure to replace the valve lifter and guides to correct customer concerns of Poor Engine Performance, Engine Misfires, Malfunction Indicator Lamp (MIL) Illuminated - DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 Set.
Trouble codes it names: P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 23-NA-043 | Service bulletin | Feb 26, 2024 | 10251355 | PDF, 493 KB |
| 23-NA-043 | Service bulletin | May 8, 2023 | 10236318 | PDF, 71 KB |
| 23-NA-043 | Service bulletin | Apr 19, 2023 | 10235766 | PDF, 495 KB |
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 3 model years
Cadillac 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 8 model years this bulletin names have filed 3,991 complaints with NHTSA since 2015. 2,095 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 2021 Chevrolet Silverado, the 102 owners who gave an odometer reading for Engine reported it at a median of 63,000 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
I own a 2021 Cadillac Escalade that falls under the manufacturer recall issued by GM/Cadillac for engine problems associated with this specific make, model, and year. I received an official recall notice via both email and U.S. Postal Service, instructing me to take my vehicle to my local dealership to have the recall addressed.
2021 Cadillac Escalade · Engine · filed with NHTSA Aug 2, 2025
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
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 group184 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 |
|---|---|---|---|
| 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… |
| N262552620 | Service campaign | May 11, 2026 | Certain vehicles may have a condition that could cause the cylinder 2 glow plug to fail. If this failure occurs, the Malfunction Indicator… |
| 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, GMC and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 23-NA-043 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 23-NA-043 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.
Which vehicles does 23-NA-043 cover?
The manufacturer filed it against 8 model years across 3 brands (Chevrolet, GMC and Cadillac): 2021 Cadillac Escalade, 2021 Chevrolet Silverado, 2020 Chevrolet Silverado, 2021 Chevrolet Suburban, 2021 Chevrolet Tahoe, 2021 GMC Sierra and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.