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Manufacturer communication · Service bulletin · 3 brands

GM bulletin 20-NA-038

What it saysThis informational bulletin explains the difference in AFM and DFM engines and what is and is not activated during this occurrence. NHTSA’s full summary ↓

GM filed this with NHTSA as a service bulletin dated Jul 23, 2024, received Apr 1, 2022, about the fuel/propulsion system — 2 documents under this number. It names 135 model years across Chevrolet, GMC and Cadillac (2016–2024). 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 communication

This informational bulletin explains the difference in AFM and DFM engines and what is and is not activated during this occurrence.

Kind Service bulletin Manufacturer date Jul 23, 2024 Received by NHTSA Apr 1, 2022 Components Fuel/Propulsion System, Engine First dated Mar 16, 2022

Documents filed under this number

DocumentKindDatedNHTSA idAt NHTSA
20-NA-038Service bulletinJul 23, 202411006377PDF, 159 KB
20-NA-038Service bulletinMar 16, 202210209465PDF, 557 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 them

Chevrolet 79 model years

and 23 more on this site: 2024 Chevrolet Silverado 3500HD, 2023 Chevrolet Silverado 3500HD, 2022 Chevrolet Silverado 3500HD, 2021 Chevrolet Silverado 3500HD, 2020 Chevrolet Silverado 3500HD, 2024 Chevrolet Suburban, 2023 Chevrolet Suburban, 2022 Chevrolet Suburban, 2021 Chevrolet Suburban, 2020 Chevrolet Suburban, 2019 Chevrolet Suburban, 2018 Chevrolet Suburban, 2017 Chevrolet Suburban, 2016 Chevrolet Suburban, 2024 Chevrolet Tahoe, 2023 Chevrolet Tahoe, 2022 Chevrolet Tahoe, 2021 Chevrolet Tahoe, 2020 Chevrolet Tahoe, 2019 Chevrolet Tahoe, 2018 Chevrolet Tahoe, 2017 Chevrolet Tahoe, 2016 Chevrolet Tahoe.

Also filed against model years this site has no page for: 2024 Chevrolet 3500HD; 2020 Chevrolet 4500; 2022 Chevrolet 4500; 2020 Chevrolet 4500HD; 2021 Chevrolet 4500HD; 2022 Chevrolet 4500HD; 2023 Chevrolet 4500HD; 2020 Chevrolet 4500XD; 2021 Chevrolet 4500XD; 2022 Chevrolet 4500XD; 2020 Chevrolet 5500HD; 2021 Chevrolet 5500HD; 2022 Chevrolet 5500HD; 2020 Chevrolet 5500XD; 2021 Chevrolet 5500XD; 2022 Chevrolet 5500XD.

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 database

Owners of the 119 model years this bulletin names have filed 19,599 complaints with NHTSA since 2015. 8,017 of them name Engine, Fuel/Propulsion 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.

On the 2019 Chevrolet Silverado, the 142 owners who gave an odometer reading for Engine reported it at a median of 71,396 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.

Car has what is called the "chevy shake" which effects almost all models from 2015-2017. Car shakes violently at times. Paid for repairs. This should be a recall as it is with other Escalade models and GM models of the same chassis..car has extreme rumble at times and is difficult to steer. While in motion at speeds of 45-70 this happens

2016 Cadillac Escalade · Engine · filed with NHTSA Jun 20, 2019

*takata recall* I have been noticing a lot of different issues with my 2017 Tahoe premier. The engine block is a deep rust color. Engine is extremely hot even hours later after parking. There is a thick black sludge that is on nearly every part under the truck. I started hearing a ticking noise that sped up as my driving speed increases.

2017 Chevrolet Tahoe · Engine · filed with NHTSA Aug 23, 2018

The contact owned a 2024 GMC Sierra 2500 HD. The contact stated that after parking the vehicle at night and plugging in the engine block heater to a standard 110-Volt outlet with an extension cord; 15-minutes later neighbors were screaming to the contact to exit the residence because the vehicle had caught on fire, and the residence was…

2024 GMC Sierra 2500HD · Engine · filed with NHTSA Nov 25, 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 fuel/propulsion system

Source: same model, same component group

86 other manufacturer communications filed against these GM models under the same component group (fuel/propulsion system), newest first. The eight newest are listed; the rest are on the Chevrolet list.

NumberKindDatedNHTSA’s summary
N262558690-02Service campaignSep 23, 2026General Motors has decided to conduct a Voluntary Emission Recall. Certain vehicles may have a condition which can cause the fuel pump power…
N262558690Service campaignSep 16, 2026General Motors has decided to conduct a Voluntary Emission Recall. Certain vehicles may have a condition which can cause the fuel pump power…
N242452131-02EmissionsSep 11, 2026Emission Recall. General Motors has decided to conduct a Voluntary Emission Recall involving certain 2023-2024 model year Chevrolet Colorad…
N262558690-01Service campaignSep 1, 2026Emission Recall. General Motors has decided to conduct a Voluntary Emission Recall. Certain vehicles listed above may have a condition whic…
N242452130-01Service campaignAug 4, 2026Certain vehicles may have a condition in which the Engine Control Module (ECM) does not sufficiently control fuel injector flow rate under c…
661.40Over-the-air updateMay 27, 2026• Surround Vision Recorder, a new feature that allows you to record, watch, and save video from your vehicle's cameras • Security Recording…
N252516900-01EmissionsFeb 19, 2026Emission Recall. General Motors has decided to conduct a Voluntary Emission Recall. Certain vehicles listed above may have a condition whi…
N252516900EmissionsFeb 5, 2026Emission Recall. General Motors has decided to conduct a Voluntary Emission Recall. Certain vehicles listed above may have a condition whi…

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.

Photo: Christian Buehner / Unsplash

Common questions

Source: NHTSA, 49 CFR 579.5

Is GM 20-NA-038 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 20-NA-038 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 20-NA-038 cover?

The manufacturer filed it against 135 model years across 3 brands (Chevrolet, GMC and Cadillac): 2024 Cadillac CT5, 2023 Cadillac CT5, 2022 Cadillac CT5, 2020 Cadillac CT6, 2019 Cadillac CT6, 2019 Cadillac CTS and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.