GM bulletin PIT6401
What it saysThis Preliminary information communicates a diagnostic tip on how to resolve a issue of the horn sounding when vehicle doors are being closed and the key in vehicle reminder set to off. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Jun 19, 2025, received Jun 30, 2025. It names 103 model years across Chevrolet, GMC, Buick and Cadillac (2020–2026). 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 · Buick · Cadillac.
Get the next GM bulletin for your model by email Weekly, only when something new is filed. Nothing else; one-click unsubscribe.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis Preliminary information communicates a diagnostic tip on how to resolve a issue of the horn sounding when vehicle doors are being closed and the key in vehicle reminder set to off.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| PIT6401 | Service bulletin | Jun 19, 2025 | 11019846 | PDF, 181 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 38 model years
Also filed against model years this site has no page for: 2025 Chevrolet Brightdrop 400; 2026 Chevrolet Brightdrop 400; 2025 Chevrolet Brightdrop 600; 2026 Chevrolet Brightdrop 600.
GMC 30 model years
and 19 more on this site: 2026 GMC Sierra, 2025 GMC Sierra, 2024 GMC Sierra, 2023 GMC Sierra, 2022 GMC Sierra, 2026 GMC Sierra 2500HD, 2025 GMC Sierra 2500HD, 2024 GMC Sierra 2500HD, 2026 GMC Sierra 3500HD, 2025 GMC Sierra 3500HD, 2024 GMC Sierra 3500HD, 2026 GMC Terrain, 2025 GMC Terrain, 2026 GMC Yukon, 2025 GMC Yukon, 2024 GMC Yukon, 2023 GMC Yukon, 2022 GMC Yukon, 2021 GMC Yukon.
Also filed against model years this site has no page for: 2022 GMC Hummer EV Pickup; 2026 GMC Hummer EV Pickup; 2026 GMC Hummer EV SUV.
Buick 6 model years
Cadillac 29 model years
and 21 more on this site: 2025 Cadillac CT5, 2024 Cadillac CT5, 2023 Cadillac CT5, 2022 Cadillac CT5, 2021 Cadillac CT5, 2020 Cadillac CT5, 2026 Cadillac Escalade, 2025 Cadillac Escalade, 2024 Cadillac Escalade, 2023 Cadillac Escalade, 2022 Cadillac Escalade, 2021 Cadillac Escalade, 2026 Cadillac Lyriq, 2025 Cadillac Lyriq, 2024 Cadillac Lyriq, 2023 Cadillac Lyriq, 2026 Cadillac Optiq, 2025 Cadillac Optiq, 2026 Cadillac Vistiq, 2025 Cadillac XT4, 2024 Cadillac XT4.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
Email me new GM bulletins for one of these models
A weekly email, sent only in a week when GM files something new with NHTSA for the model you pick — service bulletins, campaigns, warranty extensions, over-the-air notices, every model year. Nothing else is sent; one-click unsubscribe in every message. Separate from recall alerts.
What owners reported
Source: NHTSA complaint databaseOwners of the 96 model years this bulletin names have filed 10,485 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, Buick and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM PIT6401 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 PIT6401 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 PIT6401 cover?
The manufacturer filed it against 103 model years across 4 brands (Chevrolet, GMC, Buick and Cadillac): 2026 Buick Envision, 2025 Buick Envision, 2024 Buick Envision, 2023 Buick Envision, 2022 Buick Envision, 2021 Buick Envision and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.