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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

Bulletins, newest first
43-0882026-07-02. 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."
43-0802026-06-17. Service bulletin. ELECTRICAL SYSTEM. "KW: A new recommended repair has been added to verify the software level and close the campaign in SIR.The repair procedure has been updated with additional note boxes for clear instructions. PB: The repair procedure has been updated with additional note boxes for clear instructions."
26PACA2026-06-03. Service bulletin. STEERING. Updated cross shaft and bearing installation steps have been added to the repair procedures.
99-0512026-06-03. 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.
46-0282026-06-03. 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.
E3382026-05-06. Service campaign. ENGINE. Certain EPA21 PACCAR MX engines are equipped with PHINIA fuel injectors that do not meet PHINIA’s manufacturing specifications.
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.
15-0342026-03-05. Service campaign. STEERING. Battery Electric Vehicle (BEV) de-energizing and re-energizing procedures have been added to the bulletin for Peterbilt Model 520 BEV.
46-0242026-02-05. 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.
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.
46-0242026-01-06. Service bulletin. ELECTRICAL SYSTEM. Certain Battery Electric Vehicles that are subject to California Air Resources Board (CARB) regulations have Vehicle Emissions Control Information (VECI) labels that are missing the CARB Enhanced EV and FCEV Statement.
15-0342026-01-06. Service bulletin. STEERING. Certain Kenworth L770 and Peterbilt Model 520 chassis may encounter a slight increase in effort in the right-hand steering shaft when turning the wheel.
46-0192025-12-05. Service bulletin. UNKNOWN OR OTHER. Repair procedures and warranty information for model 520EV are now available. Certain Peterbilt 579EV and 520EV chassis have the First Responder Guide (FRG) label incorrectly showing the cut loop on the wrong side and are missing the Low Voltage Battery Disconnect Switch and Do Not Jump Start labels. These labels are now available for installation.
01-0902025-12-05. 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.
R24052025-11-05. 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.
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"
CE0332025-08-05. Warranty extension. ENGINE. 32 fuel injector part numbers (16 for MX-11 and 16 for MX-13) have been added to this warranty policy.
E3232025-08-05. Service bulletin. ENGINE. A required spacer tool set is now available to streamline the injector replacement process. The spacer tool set allows certain fuel system components to be loosened instead of removed to provide access to the injectors. See Bulletin 98-031 for details. Tools are not reimbursable through this Bulletin.
R2306 - PB2025-07-02. Service bulletin. ENGINE. All EMUX retrofit procedures updated to make it clear that the VECU3 must have software updated and vehicle mileage confirmed correct before updating the Digital Display. Parts and Procedure section also updated to include the Vehicle Emissions Control Information label ordering and installation instructions. This label is required for all chassis involved in R2306. Included additional reference to Cummins bulletin C7014 in the procedure section for ordering emissions labels.
E3182025-07-02. Service bulletin. ENGINE; FUEL/PROPULSION SYSTEM. Newly designed fuel injectors are available for EPA2021 compliant PACCAR MX-series engines to optimize engine performance. Injectors must be replaced as a full set (6 injectors) and associated software must be updated at the same time.
98-0302025-06-05. Service bulletin. ELECTRICAL SYSTEM. 5/29/2025: A new Ethernet Multiplexed Architecture (EMUX) Service Tool Kit service manual (SM034-022) has been released to provide general use information. The new EMUX Service Tool Kit improves cab & chassis electrical troubleshooting efficiency, while reducing risk of component damage. 4/29/2025: The Ethernet Multiplexed Architecture (EMUX) Service Tool Kit and individual kit components are now available to order. Dealers that have received their first kit may order an additional kit. The EMUX Service Tool Kit Part number has been updated to match OEM drawings (P74-1045-001). Individual kit component part numbers can be found in the Reference Bill of Materials sheet. The new EMUX Service Tool Kit improves cab & chassis electrical troubleshooting efficiency, while reducing risk of component damage. Information Only New diagnostic tool is required to support PACCAR Ethernet Multiplexed Architecture (EMUX). The EMUX Service Tool Kit will help improve cab & chassis electrical troubleshooting efficiency, while reducing the risk of component damage.
25PBC2025-05-06. Service bulletin. ELECTRICAL SYSTEM. Safety Recall – Interim Notification Certain Battery Electric Vehicle (BEV) chassis equipped with certain Accelera High Voltage Interlock Loop (HVIL)circuit configurations may experience a sudden loss of high voltage power with unintended opening of electrical contactors, which may occur without warning. This can result in a loss of propulsion and may increase the risk of a crash. This bulletin will be updated once parts and procedures are available.
46-0162025-05-06. Service campaign. ELECTRICAL SYSTEM. 4/29/2025: Campaign A software update is available for 520EV and 579EV Battery Electric Vehicles. This software update corrects or improves certain functions. Software update procedures have been revised. Campaign start date is 12/05/2024. Campaign A software update is available for 520EV and 579EV Battery Electric Vehicles. This software update corrects or improves certain functions. Campaign start date is 12/05/2024.
25PBC2025-05-06. Service bulletin. ELECTRICAL SYSTEM. Certain Peterbilt Battery Electric Vehicle (BEV) chassis equipped with certain Accelera High Voltage Interlock Loop(HVIL) circuit configurations may experience a sudden loss of high voltage power with unintended opening of electrical contractors, which may occur without warning. This can result in a loss of propulsion and may increase the risk of a crash. Software version verification, along with the installation of an upgraded circuit overlay harness kit, is required to address this issue.
R2405 - PB2025-05-06. Service bulletin. ELECTRICAL SYSTEM; ENGINE; FUEL/PROPULSION SYSTEM. Due to parts availability issues, this bulletin will be divided into 2 phases. Phase 1 will enable these chassis to be brought into emissions compliancebefore 06/30/2025 to avoid fi nes and penalties. Phase 2 will include all parts that are not currently available but are necessary to bring chassis up toproduction level. This bulletin will be updated once all Phase 2 parts become available . The emissions exemption for all chassis involved in this retrofi t expires on 06/30/2025. After that date, all chassis that have not received this Retrofi t willbe out of compliance with emissions regulations and illegal to operate . NOTE If emissions exemptions are allowed to expire, vehicle owners could receive civil fines per regulation 40 CFR 19.4 up to $5,911 per engine. In addition, owners may be required to discontinue operation of the vehicle until the retrofit is completed. Campaign start date: 04/18/25

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