GMC bulletin 661.42
GMC filed this with NHTSA as a over-the-air update dated Jun 10, 2026, received Jun 25, 2026, about the unknown or other. It names 1 model year (2024). 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• If you are equipped with Diesel engine then: Improvements to accuracy for Diesel Exhaust Fluid level shown in driver display.
Document filed under this number
| Document | Kind | Dated | NHTSA id |
|---|---|---|---|
| 661.42 | Over-the-air update | Jun 10, 2026 | 11034054 |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5; the full text comes from the manufacturer or a dealer. 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. Quote it at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themA 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 661.42 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 661.42 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 661.42 cover?
The manufacturer filed it against 1 model year: 2024 GMC Sierra. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.