Service bulletins for the 2025 Peterbilt 520
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.
62 on file from NHTSA, as of 2026-10-19.
By type
By component
Only bulletins with component: Engine are shown. Show all
| P001 | 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." |
|---|---|
| P001 | 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." |
| P002 | 2026-09-23. Service bulletin. ENGINE. "KW: A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section. PB: The chassis list has been updated to include 2 chassis. The total chassis count is now 4. A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section." |
| P002 | 2026-08-27. Service bulletin. ENGINE. "KW: A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section. PB: The chassis list has been updated to include 2 chassis. The total chassis count is now 4. A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section." |
| P001 | 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 | 2026-08-25. Service bulletin. ENGINE. This optional software update is expected to be available after 08/28/2026. |
| P001 | 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 | 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." |
| P001 | 2026-08-20. Service bulletin. ELECTRICAL SYSTEM; ENGINE. Chassis list has been updated to include 10 chassis. The total chassis count is now 101. |
| 43-089 | 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 | 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. |
| 43-088 | 2026-08-20. Service bulletin. ENGINE. The procedure has been updated to include additional steps for verifying the software level on the vehicle electronic control unit (VECU2) and digital display (DD). Steps have also been added to the PACCAR Common Rail Injection 2 (PCI2) software verification. |
| 43-089 | 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. |
| 43-088 | 2026-07-23. Service bulletin. ENGINE. This optional software update is now available for chassis equipped with EMY 2021B-2023 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. |
| 43-089 | 2026-07-22. Service bulletin. ENGINE; ELECTRICAL SYSTEM. An optional software update is expected to be available on or after 07/31/26 for chassis equipped with EPA 2024 engine model year (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. |
| E318 | 2026-07-22. Service bulletin. ENGINE. The Condition, Chassis Affected, Service Action, Warranty, and Procedure sections have been updated to include the latest prognostics bulletin verbiage. The Warranty section has also been updated to include Peterbilt specific SRT codes for filing cross-division repairs. |
| 43-088 | 2026-07-21. Service bulletin. ENGINE. "The software is not yet available. The bulletin will be updated when more information is available." |
| P001 | 2026-07-02. Service campaign. ENGINE. Leveraging PACCAR’s advanced Prognostic prediction algorithms, certain PACCAR MX-11 and MX-13 EMY 2024-2026 engines will receive proactive replacement instructions for the PM sensor to maximize uptime and maintain optimal performance. |
| 43-088 | 2026-07-02. Service bulletin. ENGINE. "An optional software update will be available on 07/06/2026 for chassis equipped with EMY 2021B-2023PACCAR MX-11 and MX-13 engines. This update provides customers with additional time to service theirtrucks before a DEF-related derate occurs. The software is being offered to customers in alignment withrecently updated regulatory agency guidance." |
| 99-051 | 2026-06-03. Emissions. ENGINE. There 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. |
| E338 | 2026-05-06. Service campaign. ENGINE. Certain EPA21 PACCAR MX engines are equipped with PHINIA fuel injectors that do not meet PHINIA’s manufacturing specifications. |
| E326 | 2026-05-06. Emissions. ENGINE; ELECTRICAL SYSTEM. EPA17-24 MX Fuel Injector Connector - This bulletin has been revised to include all EPA17-24 and CARB24 PACCAR MX engines. |
| 01-090 | 2025-12-05. Service bulletin. ENGINE. Repair procedures and warranty information for model 520EV are now available. The cab heater coolant system on Peterbilt 579EV and 520EV models may not deaerate properly, causing pump malfunctions and inadequate cab heating. Update coolant deaeration return line parts and procedures are now available to release trapped air back to the reservoir. |
| R2405 | 2025-11-05. Service bulletin. ENGINE; ELECTRICAL SYSTEM. All parts necessary to complete Phase 2 of this bulletin are now available. This retrofit provides certain chassis equipped with Cummins X15N (Natural Gas) engines with production level parts to replace preproduction parts installed at the time of manufacture. |
| CE033 | 2025-08-05. Warranty extension. ENGINE. 32 fuel injector part numbers (16 for MX-11 and 16 for MX-13) have been added to this warranty policy. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.