2026 Peterbilt 579 TSBs

PB: The chassis list has been updated to include 1 chassis. The total chassis count is now 10. 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."

PB: The chassis list has been updated to include 1 chassis. The total chassis count is now 10. 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 9.

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."

The total chassis count is now 8.

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 7. For Kenworth: Chassis list has been updated to include 1 chassis. The total chassis count is now 8."

(PB) Certain Model 367 / 389 / 567 / 579 / 589 have updated GHG labels available for order and installation.

This is not a stand-alone procedure. Cummins Quickserve troubleshooting will specify the use of these procedures while troubleshooting specific fault codes.

Certain out of specification parameters may result in customer dissatisfaction. (PB) Certain Peterbilt Model 579 chassis may have certain software parameters out of specification. Certain out of specification parameters may result in customer dissatisfaction.

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

The original wiring and fuse are insufficient for electrical system operation and protection.

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.

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.

Engine Model Year (EMY) 2026 MX-11 and MX-13 Operators Manuals.

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

receive proactive replacement instructions for the NOx sensor after catalyst to maximize uptime and maintain optimal performance.

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.

engines.

Vehicle Electronic Control Unit (VECU3) software update.

system inspection process for all engine air intake system components.

When troubleshooting Cummins X15 fault codes 555 or 556, follow this additional testing, inspection, and documentation procedure to help identify the root cause of dusted engines. This is not a stand-alone process but must be used alongside Cummins troubleshooting steps. Cummins Quickserve will reference this bulletin for fault codes 555 or 556.

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"

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

display as --- after programming.

on ServiceNet cannot be utilized for certain pre-production Battery Electric Vehicle (BEV) chassis.

installation.

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.

transmission, featuring a more durable design for enhanced long-term performance.

Eaton Endurant transmissions, TCM software version R5.5 or later and an AT5 controller, where the TASPS fails. Please see the Eaton bulletin TAIB-1015 in the Attachments section for details. PB: A Transmission Control Module (TCM) software update is now available for certain Model 567, 579, and 589 chassis with Eaton Endurant transmissions, TCM software version R5.5 or later and an AT5 controller, where the TASPS fails. Please see the Eaton bulletin TAIB-1015 in the Attachments section for details.

W990 chassis with PACCAR TX-12 and TX-18 transmissions, TCM software version R5.5 or later and an AT5 controller, where the TASPS fails. PB: A Transmission Control Module (TCM) software update is now available for certain Model 537, 548, 567, 579, and 589 chassis with PACCAR TX-12 and TX-18 transmissions, TCM software version R5.5 or later and an AT5 controller, where the TASPS fails.

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."

midship one-piece aluminum crossmembers.

housings.

The DAVIE4 cache must be cleared before attempting to reprogram a chassis that is experiencing problems to ensure the latest version of software is installed. Follow all steps in the attached procedures before submitting a TCS case."

Early wear of the polyurethane exhaust stack isolators may occur on certain Peterbilt chassis due to excessive heat.

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.