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Service bulletins for the 2026 Kenworth L770

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.

14 on file from NHTSA, as of 2026-10-19.

By type

By component

Bulletins, newest first
42-0702026-10-17. Service bulletin. UNKNOWN OR OTHER. Due to supplier constraints, an authorized aftermarket surge tank has been made available.
P0012026-09-29. 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."
43-0892026-08-25. Service bulletin. ENGINE. This optional software update is expected to be available after 08/28/2026.
24KWC/24PBC2026-08-20. Service bulletin. STEERING. Updated Sheppard Steering Gear Classification Tool link in Inspection Procedure
43-0892026-08-20. 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.
43-0892026-08-20. 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.
43-0892026-08-01. 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.
43-0892026-07-22. 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.
99-0522026-07-20. 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.
26PACA2026-06-03. Service bulletin. STEERING. Updated cross shaft and bearing installation steps have been added to the repair procedures.
E3262026-05-06. 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.
26PACA2026-02-18. 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.
25PACF2026-01-06. 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.
25PACF2025-09-03. Service campaign. EXTERIOR LIGHTING. Procedures are now available for Phase 1 chassis equipped with Internal Combustion Engines (ICE) and Vehicle Electronic Control Unit (VECU) part number Q21-1157-013-011 / Q21-1157-013-013. Parts and procedures for Phase 2 chassis will be available at a later date. This bulletin will be updated at that time. Please refer to the condition section for more details. Certain Ethernet Multiplexed Architecture (EMUX) chassis fail to conform to Federal and Canada Motor Vehicle Safety Standards (FMVSS/CMVSS) No. 108. Delayed or unsteady illumination of the vehicle’s stop lamps, reverse lamps, turn signal lamps and inadvertent change in headlamp illumination or lift axle position may"

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.