2025 Peterbilt 520 TSBs

certain Engine Model Year (EMY) 2024-2026 PX-7 and PX-9 Operators Manuals.

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.

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.

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.

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.

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.

receive proactive replacement instructions for the PM sensor to maximize uptime and maintain optimal performance.

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."

certain Engine Model Year (EMY) 2025 MX-11 and MX-13 Operators Manuals.

without a check valve in the power steering system.

specifications.

engines.

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.

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 vehicles stop lamps, reverse lamps, turn signal lamps and inadvertent change in headlamp illumination or lift axle position may"

Injectors must be replaced as a full set (6 injectors) and associated software must be updated at the same time.

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

PCI-2 software on these chassis must be reverted from NA202 to NA201 (Pack 2 injectors) or from NA206 to NA191 (Pack 1 injectors) to prevent incorrect STOP lamp display.

Fuel Filters must be changed before first cleaning. EPA2021 injector cleaning is referenced in RMI for certain injector faults. Complete the procedures in E290. Discard any previous versions of E290 procedures always use the most current document from the link in the bulletin.

The update must be completed before performing a DAVIE4 Learn dash switches procedure to fix intermittent dash switch functionality.

display as --- after programming.

control unit (VECU2) and digital display (DD). Steps have also been added to the PACCAR Common Rail Injection 2 (PCI2) software verification.

may intermittently lose electrical continuity at one or more C40 connector pins. This can occur without warning and cause loss of propulsion, increasing the risk of a crash. Certified BEV technicians will inspect the C40 connector and replace the cradle harness, if necessary. This safety recall defect is identical to 25KWD and applies to certain Canadian chassis added on 07/02/2026. (PB): Certain Peterbilt Model 220 Battery Electric Vehicle (BEV) chassis equipped with certain DANA cradle harnesses may intermittently lose electrical continuity at one or more C40 connector pins. This can occur without warning and cause loss of propulsion, increasing the risk of a crash. Certified BEV technicians will inspect the C40 connector and replace the cradle harness, if necessary. This safety recall defect is identical to 25PBD and applies to certain Canadian chassis added on 07/02/2026."

Model 520 BEV.

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.

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.

Emissions Control Information (VECI) labels that are missing the CARB Enhanced EV and FCEV Statement.

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.

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.

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.

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.

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.

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.

Software has been campaigned for both processes, and software assistance is no longer required. All EMUX jumper harness retrofit procedures have been updated to include a soft reverification step and procedures for 520, 567 car carrier, and 2.1m MD have been updated to include R&R procedures for VECU3. Parts Matrix has been updated VECU3 has been added to numerous chassis.

The EMUX Service Tool Kit will help improve cab & chassis electrical troubleshooting efficiency, while reducing the risk of component damage.

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."

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."

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."

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."

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."

Total chassis count is now 49. PB - The chassis list has been updated to include10 chassis. The total chassis count is now 111."

The total chassis count is now 101.

latest prognostics bulletin verbiage. The Warranty section has also been updated to include Peterbilt specific SRT codes for filing cross-division repairs.

The bulletin will be updated when more information is available."

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."

Software updates are now available to complete this campaign.

steering shaft when turning the wheel.

Steer Axle have been identified as having steering arm and/or tie rod arm fasteners that may be improperly torqued and can be at risk of failing. If both fasteners in either steering arm or tie rod arm fail, there may be a loss of steering control, which could increase the risk of a crash. Affected chassis will have all steering arm and tie rod arm bolts removed, replaced with new bolts, and torqued properly.

with a PACCAR 20k Steer Axle have been identified as having steer arm and/or tie rod arm fasteners that may be improperly torqued and can be at risk of failing. If both fasteners in either steering arm or tie rod arm fail, there may be a loss of steering control, which could increase the risk of a crash. At this time, parts are not available to complete the necessary repairs. This bulletin will be updated when parts become available.

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.

Operators Manuals are incorrect.

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."

Steering Gears repaired under this bulletin MUST be entered into the Serial Number Tracking Form for 24PBC.

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.

Certain Vehicle Model Year 2021-2025 Peterbilt chassis configured for trailer towing require a software update for the Bendix EC80 ABS ECU. Software update procedures for certain Battery-Electric Vehicles (BEV) and EC80 ABS ECU part numbers are not yet available. This bulletin will be updated when software update procedures are available for these chassis. Safety Recall publish date: 1/10/25

This may cause an intermittent warning light on the dash display.