Kenworth bulletin 99-051
Kenworth filed this with NHTSA as a emissions communication dated May 18, 2026, received Jun 3, 2026, about the engine. It names 4 model years (2025). A emissions communication 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 communicationThere is an update to the CARB Base Emissions Warranty Limits table and Manufacturer’s Warranty Coverage section in certain Engine Model Year (EMY) 2025 MX-11 and MX-13 Operator’s Manuals.
Document filed under this number
| Document | Kind | Dated | NHTSA id |
|---|---|---|---|
| 99-051 | Emissions | May 18, 2026 | 11033372 |
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 themAlso filed against: 2025 Kenworth L770; 2025 Kenworth T680; 2025 Kenworth T880; 2025 Kenworth W990.
None of these model years has a page on this site (it covers EPA-certified cars, trucks and SUVs from 2016), so the bulletin is listed here on its own.
Common questions
Source: NHTSA, 49 CFR 579.5Is Kenworth 99-051 a recall?
No. A emissions communication 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.
Is the 99-051 repair free?
A emissions communication 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 99-051 cover?
The manufacturer filed it against 4 model years: 2025 Kenworth L770, 2025 Kenworth T680, 2025 Kenworth T880, 2025 Kenworth W990. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.