# Service bulletins for the 2026 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.

30 bulletins from NHTSA, as of 2026-10-19.

- [42\-070](/bulletins/11038569.md), 2026-10-17, Service bulletin: UNKNOWN OR OTHER. Due to supplier constraints, an authorized aftermarket surge tank has been made available.
- [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."
- [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."
- [24KWC/24PBC](/bulletins/11036296.md), 2026-08-20, Service bulletin: STEERING. Updated Sheppard Steering Gear Classification Tool link in Inspection Procedure
- [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.
- [46\-029](/bulletins/11036290.md), 2026-08-20, Service bulletin: ELECTRICAL SYSTEM. When DAVIE version 26.21.2 is used to update the VECU3 to software version 3.4.46.0, the VECU3 5071 component group may display as \-\-\- after programming.
- [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.
- [43\-089](/bulletins/11035151.md), 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.
- [25KWD 25PBD](/bulletins/11035096.md), 2026-07-20, Service campaign: ELECTRICAL SYSTEM; FUEL/PROPULSION SYSTEM. Additional US chassis have been added, along with additional Canadian chassis under identical safety recall 26PACB.
- [99\-052](/bulletins/11035095.md), 2026-07-20, Service bulletin: UNKNOWN OR OTHER. There is an update to the Base Emissions Warranty Limits table \[PR1.1\]and general certification information in certain Engine Model Year \(EMY\) 2026 MX\-11 and MX\-13 Operator’s Manuals.
- [P001](/bulletins/11034397.md), 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.
- [26PACA](/bulletins/11033376.md), 2026-06-03, Service bulletin: STEERING. Updated cross shaft and bearing installation steps have been added to the repair procedures.
- [46\-028](/bulletins/11033352.md), 2026-06-03, Service campaign: STEERING. Certain Peterbilt Model 520 BEV chassis with an Accelera Power Control and Accessory System \(PCAS\) were manufactured without a check valve in the power steering system.
- [E340](/bulletins/11032287.md), 2026-05-06, Emissions: ENGINE. KW Certain vehicle model year 2026 Kenworth chassis equipped with EMY2025 PACCAR MX engines require an amended engine label. The engine label is now available for order and installation. PB Certain vehicle model year 2026 Peterbilt chassis equipped with EMY2025 PACCAR MX engines require an amended engine label. The engine label is now available for order and installation.
- [E339](/bulletins/11032286.md), 2026-05-06, Emissions: ENGINE. 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.
- [E326](/bulletins/11032284.md), 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.
- [15\-034](/bulletins/11029729.md), 2026-03-05, Service campaign: STEERING. Battery Electric Vehicle \(BEV\) de\-energizing and re\-energizing procedures have been added to the bulletin for Peterbilt Model 520 BEV.
- [26PACA](/bulletins/11028852.md), 2026-02-18, Service campaign: STEERING. KW: Certain Kenworth L770 chassis may have Right\-Hand \(RH\) steering cross shaft bearing mounting holes that are misaligned, resulting in increased stress on the steering cross shaft on the Right\-Hand Stand\-Up \(RHSU\) controls configuration. Failure of the RH steering cross shaft could result in the loss of RH steering control which may increase the risk of a crash. PB: Certain Peterbilt Model 520 / 520 BEV chassis may have Right\-Hand \(RH\) steering cross shaft bearing mounting holes that are misaligned, resulting in increased stress on the steering cross shaft on the Right\-Hand Stand\-Up \(RHSU\) controls configuration. Failure of the RH steering cross shaft could result in the loss of RH steering control which may increase the risk of a crash.
- [46\-024](/bulletins/11028311.md), 2026-02-05, Service bulletin: UNKNOWN OR OTHER. CARB Label Procedure Update The repair procedure removes the aftermarket change request, adds GHG label inspection, and directs dealers to open a TCS365 case to order new labels. Warranty codes for inspection and label replacement have been updated. Certain Battery Electric Vehicles that are subject to California Air Resources Board \(CARB\) regulations have GHG labels that are missing the CARB Enhanced EV and FCEV Statement.
- [25PACF](/bulletins/11027067.md), 2026-01-06, Service bulletin: EXTERIOR LIGHTING. Parts and procedures are now available for all affected chassis equipped with Vehicle Electronic Control Unit \(VECU\) part number Q21\-1157\-013\-011 / Q21\-1157\-013\-013 / Q21\-1157\-002\-002 / Q21\-1157\-004\-004 / Q21\-1157\-006\-006 / Q21\-1157\-009\-009. See attached Parts Matrix for required parts per chassis.

More: [the next page](/v1/vehicles/2026_peterbilt_520/bulletins?cursor=2026-01-06_11027067) (JSON)

JSON: [/v1/vehicles/2026_peterbilt_520/bulletins](/v1/vehicles/2026_peterbilt_520/bulletins)

[Report an error on this page](https://github.com/wenmar-pro/wenmar-open/issues/new?template=data_correction.yml&title=Data%20correction%3A%202026%20Peterbilt%20520&page=https%3A%2F%2Fopen.wenmarpro.com%2Fmakes%2Fpeterbilt%2F520%2F2026%2Fbulletins&vehicle=2026%20Peterbilt%20520)