GM bulletin 21-NA-279
What it saysThis service bulletin provides a procedure to replace the starter if found the cause of the rattle noise. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Sep 19, 2023, received Oct 14, 2023, about the engine. It names 33 model years across Chevrolet, GMC, Buick and Cadillac (2019–2023). 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 · Buick · 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 starter if found the cause of the rattle noise.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 21-NA-279 | Service bulletin | Sep 19, 2023 | 10243981 | PDF, 494 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 5 model years
GMC 4 model years
Buick 3 model years
Cadillac 21 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 33 model years this bulletin names have filed 1,437 complaints with NHTSA since 2015. 362 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.
I was driving on express way 96W Left lane busy 5 o'clock traffic Car just died it was stop n go I could have been killed if it wasn't for a man that stopped behind me he couldn't help another person stopped and push the car in N To a grass area where at least I wouldn't be smashed in Called 911 state police inform help van He didn't…
2020 Chevrolet Blazer · Engine · filed with NHTSA Oct 25, 2023 · ODI 11551752
While driving on a very busy highway going downhill when suddenly the vehicle started feeling abnormal like it was going to turn off automatically, heard an abnormal grinding noise coming from the engine the vehicle dropped speed drastically and the check engine light turned on , luckily we were on a part of the road where I merged…
2021 Cadillac CT5 · Engine · filed with NHTSA Feb 12, 2026 · ODI 11717706
The contact owns a 2020 Cadillac XT4. The contact stated while driving 30 MPH and depressing the brake pedal, the vehicle failed to respond as needed. Several unknown warning lights were illuminated on the instrument panel. The contact stated that after purchasing the vehicle, the vehicle started shaking abnormally while driving.
2020 Cadillac XT4 · Engine · filed with NHTSA Mar 13, 2025 · ODI 11648185
In depth: 2020 Chevrolet Blazer 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 group129 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 |
|---|---|---|---|
| N262570770-03 | Service campaign | Oct 16, 2026 | Certain vehicles may have a condition in which the thermal break tabs induce stress into the radiator causing a coolant leak. Dealers are t… |
| N262570770-02 | Service campaign | Sep 25, 2026 | Certain vehicles may have a condition in which the thermal break tabs induce stress into the radiator causing a coolant leak. Dealers are to… |
| N262570770-01 | Service campaign | Sep 18, 2026 | Certain vehicles may have a condition in which the thermal break tabs induce stress into the radiator causing a coolant leak. Dealers are to… |
| N262570770 | Service campaign | Sep 15, 2026 | Certain vehicles may have a condition in which the thermal break tabs induce stress into the radiator causing a coolant leak. Dealers are to… |
| 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… |
| N262546590-01 | Service campaign | Jul 15, 2026 | Certain vehicles listed above, may have a condition where coolant leaks from the radiator hose quick connect at the radiator inlet. This sp… |
| 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… |
| N252540910 | Service campaign | Feb 25, 2026 | Service Update. Certain vehicles listed above may have a condition in which a quality issue with the engine was identified. Dealers will re… |
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, Buick and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 21-NA-279 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 21-NA-279 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 21-NA-279 cover?
The manufacturer filed it against 33 model years across 4 brands (Chevrolet, GMC, Buick and Cadillac): 2023 Buick Envision, 2022 Buick Envision, 2021 Buick Envision, 2023 Cadillac CT4, 2022 Cadillac CT4, 2021 Cadillac CT4 and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.