GMC bulletin 662.20
GMC filed this with NHTSA as a over-the-air update dated Aug 8, 2026, received Jun 26, 2026, about the unknown or other — 8 documents under this number. It names 9 model years (2024–2026). A over-the-air update is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communication• Improvements to active cabin ventilation • Additional protection for the health of your battery • Improvements to the software update system • Fixes to help ensure proper functionality for heating and cooling features. • Improvements to night mode lights for shifting gears. • Fixes for Daytime Running Lamps turning on when set to Off. • Fixes to help prevent erroneous missing key messages on driver display. • Fixes for accuracy of low tire pressure alert. • Fixes for speed threshold for pedestrian alerts. • Improvements to help reduce check engine light activation and emissions system messages. • Improves behavior of aero shutter system in freezing temperatures • Improvements to reliability when extending the running boards on your vehicle.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 662.20 | Over-the-air update | Aug 8, 2026 | 11036470 | PDF, 200 KB |
| 662.20 | Over-the-air update | Jul 16, 2026 | 11035390 | PDF, 195 KB |
| 662.20 | Over-the-air update | Jul 8, 2026 | 11036504 | PDF, 200 KB |
| 662.20 | Over-the-air update | Jul 8, 2026 | 11035384 | PDF, 195 KB |
| 662.20 | Over-the-air update | Jul 8, 2026 | 11035377 | PDF, 197 KB |
| 662.20 | Over-the-air update | Jun 25, 2026 | 11034930 | PDF, 201 KB |
| 662.20 | Over-the-air update | Jun 23, 2026 | 11034081 | PDF, 189 KB |
| 662.20 | Over-the-air update | Jun 22, 2026 | 11034939 | PDF, 200 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 themAlso filed against model years this site has no page for: 2026 GMC Hummer EV Pickup; 2026 GMC Hummer EV SUV.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
Common questions
Source: NHTSA, 49 CFR 579.5Is GMC 662.20 a recall?
No. A over-the-air update 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 662.20 repair free?
A over-the-air update is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.
Which vehicles does 662.20 cover?
The manufacturer filed it against 9 model years: 2025 GMC Hummer EV, 2024 GMC Hummer EV, 2026 GMC Sierra, 2025 GMC Sierra, 2024 GMC Sierra, 2025 GMC Sierra 2500HD and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.