GM bulletin PIT6400A
What it saysThis PI Communications information on an alternative product dealers can use to perform 19-NA-255: Wax Coating on Frame Peeling, Metal Shows Corrosion/Rusting due to issue with getting product from current supplier… NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Jan 16, 2026, received Jan 19, 2026. It names 121 model years across Chevrolet, GMC and Cadillac (2016–2026). 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 PI Communications information on an alternative product dealers can use to perform 19-NA-255: Wax Coating on Frame Peeling, Metal Shows Corrosion/Rusting due to issue with getting product from current supplier listed in the bulletin.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| PIT6400A | Service bulletin | Jan 16, 2026 | 11027698 | PDF, 111 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 55 model years
and 15 more on this site: 2019 Chevrolet Silverado 3500HD, 2018 Chevrolet Silverado 3500HD, 2017 Chevrolet Silverado 3500HD, 2016 Chevrolet Silverado 3500HD, 2026 Chevrolet Suburban, 2025 Chevrolet Suburban, 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.
GMC 55 model years
and 47 more on this site: 2018 GMC Savana, 2017 GMC Savana, 2016 GMC Savana, 2026 GMC Sierra, 2025 GMC Sierra, 2024 GMC Sierra, 2023 GMC Sierra, 2022 GMC Sierra, 2021 GMC Sierra, 2020 GMC Sierra, 2019 GMC Sierra, 2018 GMC Sierra, 2017 GMC Sierra, 2016 GMC Sierra, 2026 GMC Sierra 2500HD, 2025 GMC Sierra 2500HD, 2024 GMC Sierra 2500HD, 2023 GMC Sierra 2500HD, 2022 GMC Sierra 2500HD, 2021 GMC Sierra 2500HD, 2020 GMC Sierra 2500HD, 2019 GMC Sierra 2500HD, 2018 GMC Sierra 2500HD, 2017 GMC Sierra 2500HD, 2016 GMC Sierra 2500HD, 2026 GMC Sierra 3500HD, 2025 GMC Sierra 3500HD, 2024 GMC Sierra 3500HD, 2023 GMC Sierra 3500HD, 2022 GMC Sierra 3500HD, 2021 GMC Sierra 3500HD, 2020 GMC Sierra 3500HD, 2019 GMC Sierra 3500HD, 2018 GMC Sierra 3500HD, 2017 GMC Sierra 3500HD, 2016 GMC Sierra 3500HD, 2026 GMC Yukon, 2025 GMC Yukon, 2024 GMC Yukon, 2023 GMC Yukon, 2022 GMC Yukon, 2021 GMC Yukon, 2020 GMC Yukon, 2019 GMC Yukon, 2018 GMC Yukon, 2017 GMC Yukon, 2016 GMC Yukon.
Cadillac 11 model years
and 3 more on this site: 2018 Cadillac Escalade, 2017 Cadillac Escalade, 2016 Cadillac Escalade.
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 121 model years this bulletin names have filed 18,641 complaints with NHTSA since 2015.
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.

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 PIT6400A 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 PIT6400A 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 PIT6400A cover?
The manufacturer filed it against 121 model years across 3 brands (Chevrolet, GMC and Cadillac): 2026 Cadillac Escalade, 2025 Cadillac Escalade, 2024 Cadillac Escalade, 2023 Cadillac Escalade, 2022 Cadillac Escalade, 2021 Cadillac Escalade and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.