GM bulletin 21-NA-293
What it saysThis technical bulletin provides repair information to correct a customer concern of Poor Engine Performance in Extremely Cold Weather Conditions, Charge Air Cooler Icing - Malfunction Indicator Lamp (MIL) Illuminated… NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Jan 17, 2025, received Aug 2, 2023, about the electrical system — 2 documents under this number. It names 7 model years across Chevrolet and Buick (2020–2023). 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 · Buick.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis technical bulletin provides repair information to correct a customer concern of Poor Engine Performance in Extremely Cold Weather Conditions, Charge Air Cooler Icing - Malfunction Indicator Lamp (MIL) Illuminated, DTC P0299, P0234, P0236, P00C7 Set.
Trouble codes it names: P00C7 P0234 P0236 P0299
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 21-NA-293 | Service bulletin | Jan 17, 2025 | 11013244 | PDF, 840 KB |
| 21-NA-293 | Service bulletin | Jul 28, 2023 | 10240189 | PDF, 133 KB |
What the document itself lists
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 2888338 | Engine Control Module Reprogramming with SPS for Cold Weather Engine Performance | 0.3 hrs |
Read by machine from the document NHTSA serves (7 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 3 model years
Buick 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 7 model years this bulletin names have filed 589 complaints with NHTSA since 2015. 397 of them name Engine, Power Train, Electrical System — 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 bought my car, new, on 10/1/ 2023. The middle of November i noticed the headlights randomly dimming. On 12/3/23 I to the dealership to have them looked at. I was told there was nothing wrong but make an appt. they had my car 3 times in less than 2 months. I repeatedly told them my headlights were dimming and or going off.
2023 Buick Encore · Electrical System · filed with NHTSA Apr 26, 2024
The contact owns a 2023 Chevrolet Trailblazer. The contact stated that while driving 65 MPH, the “Engine Power Reduced" message was displayed, and the vehicle was unable to accelerate above 30 MPH. No warning lights were illuminated. The vehicle returned to normal functionality, but the failure became a regular occurrence.
2023 Chevrolet Trailblazer · Engine · filed with NHTSA Sep 19, 2024
Engine light is on and vehicle is sluggish on hills and keeping up in traffic. Rpms run high if I try. Error code p0299 shows on scanning device- turbo under boost. I have 112,000 miles and need turbo replaced already. this vehicle is very well maintained. I did see a special notice for the GX version of this vehicle.
2020 Buick Encore · Power Train · filed with NHTSA Apr 23, 2024
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 electrical system
Source: same model, same component group63 other manufacturer communications filed against these GM models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 23-NA-119 | Service bulletin | Sep 3, 2025 | This service bulletin provides service procedure information to correct a customer concern of Shift to Park Displayed on DIC When Vehicle is… |
| 22-NA-242 | Service bulletin | Apr 24, 2025 | This warranty administration bulletin provides information for dealers/technicians on System Reset and Connector Reconnect Labor Code Number… |
| PIE0831 | Service bulletin | Apr 22, 2025 | This engineering information (EI) is requesting information from technicians to perform the check list provided and contact the engineer lis… |
| 24-NA-229 | Service bulletin | Apr 10, 2025 | This bulletin provides a procedure on how to check for a battery drain utilizing the Picoscope and how to measure the load on the system tha… |
| 25-NA-087 | Service bulletin | Apr 3, 2025 | This service bulletin provides information on the proper Reflective High Temperature Heat and/or Insulating Tape to use for certain repairs… |
| 13-08-116-001K | Service bulletin | Mar 31, 2025 | The intent of this service bulletin is to identify aftermarket ALDL or DLC interface devices as potential sources for causing multiple custo… |
| 25-NA-071 | Service bulletin | Mar 21, 2025 | This service bulletin provides repair procedures for radio software update version 169.4 to correct customer concerns of radio software issu… |
| 24-NA-098 | Service bulletin | Mar 21, 2025 | This service bulletin provides information for dealers/technicians on Service Programming System (SPS) Error Codes E4398, E4399, E4401, E440… |
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 Buick, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 21-NA-293 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-293 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 21-NA-293 cover?
The manufacturer filed it against 7 model years across 2 brands (Chevrolet and Buick): 2023 Buick Encore, 2022 Buick Encore, 2021 Buick Encore, 2020 Buick Encore, 2023 Chevrolet Trailblazer, 2022 Chevrolet Trailblazer and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.