# Emissions E339

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Emissions
- NHTSA id: 11032286
- Published by NHTSA: 2026\-05\-06
- Manufacturer's number: E339
- Manufacturer's date: 2026\-04\-10
- Campaign id or software version: E339
- NHTSA component: ENGINE

## NHTSA's summary

EMY25 Engine Label Replacement \- \(KW\) Certain vehicle model year 2026 Kenworth chassis equipped with EMY2025 PACCAR MX engines require a revised engine label update. \(PB\) Certain vehicle model year 2026 Peterbilt chassis equipped with EMY2025 PACCAR MX engines require a revised engine label update.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11032286-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11032286-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Engine

## Vehicles listed

- 2026 KENWORTH T880
- 2026 PETERBILT 520
- 2026 PETERBILT 567

## Other bulletins for the same vehicles and component

- [P001](/bulletins/11037541.md), 2026-09-29, Service bulletin: ENGINE. "Kenworth: Dealers should check the chassis list and SIR weekly for VIN changes. 2 chassis added to the chassis list. Peterbilt: Dealers should check the chassis list and SIR weekly for VIN changes. 10 chassis added to the chassis list."
- [E343](/bulletins/11037451.md), 2026-09-23, Service bulletin: ENGINE. An exhaust manifold slip joint seal kit is now available for EPA 2017\-2024 PACCAR MX\-13 engines.
- [P001](/bulletins/11037449.md), 2026-09-23, Service bulletin: ENGINE. "KW: The chassis list has been updated to include 1 chassis. The total chassis count is now 53. A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section. PB: The chassis list has been updated to include 8 chassis. The total chassis count is now 130. A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section."
- [P001](/bulletins/11036426.md), 2026-08-27, Service bulletin: ENGINE. "KW: The chassis list has been updated to include 1 chassis. The total chassis count is now 53. A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section. PB: The chassis list has been updated to include 8 chassis. The total chassis count is now 130. A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section."
- [43\-089](/bulletins/11036342.md), 2026-08-25, Service bulletin: ENGINE. This optional software update is expected to be available after 08/28/2026.
- [P001](/bulletins/11036339.md), 2026-08-25, Service bulletin: ENGINE. "PB: The chassis list has been updated to include 11 chassis. The total chassis count is now 122. KW: The chassis list has been updated to include 3 chassis. The total chassis count is now 52."
- [P001](/bulletins/11036297.md), 2026-08-20, Service bulletin: ENGINE. "KW \-The chassis list has been updated to include 2 chassis. Total chassis count is now 49. PB \- The chassis list has been updated to include10 chassis. The total chassis count is now 111."
- [43\-089](/bulletins/11036293.md), 2026-08-20, Service bulletin: ENGINE. This optional software update is expected to be available in late August 2026 for chassis equipped with EPA 2024 EMY 2024\-2026 PACCAR MX\-11 and MX\-13 engines. This bulletin will be updated when the software is ready. This update provides customers with additional time to service their trucks before a DEF\-related derate occurs. The software is being offered to customers in alignment with recently updated regulatory agency guidance. The procedure document has also been updated for clarity.
- [43\-089](/bulletins/11036292.md), 2026-08-20, Service bulletin: ENGINE. This optional software update is expected to be available in late August 2026 for chassis equipped with EPA 2024 EMY 2024\-2026 PACCAR MX\-11 and MX\-13 engines. This bulletin will be updated when the software is ready. This update provides customers with additional time to service their trucks before a DEF\-related derate occurs. The software is being offered to customers in alignment with recently updated regulatory agency guidance. The procedure document has also been updated for clarity.
- [43\-089](/bulletins/11035433.md), 2026-08-01, Service bulletin: ENGINE. This optional software update is expected to be available on 08/07/26 for chassis equipped with EPA 2024 EMY 2024\-2026 PACCAR MX\-11 and MX\-13 engines. This update provides customers with additional time to service their trucks before a DEF\-related derate occurs. The software is being offered to customers in alignment with recently updated regulatory agency guidance.

JSON: [/v1/bulletins/11032286](/v1/bulletins/11032286)

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