Vehicle report

2026 PETERBILT 520

Service bulletins

16 bulletins

Technical service bulletins are instructions a manufacturer sent its dealers about a known fault. They are not recalls and the work is usually not free, but they are the clearest signal of a problem the manufacturer already knows about.

P001

Service Bulletin/Repair Instructions

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

Service Bulletin/Repair Instructions

This optional software update is expected to be available after 08/28/2026.

24KWC/24PBC

Service Bulletin/Repair Instructions

Updated Sheppard Steering Gear Classification Tool link in Inspection Procedure

46-029

Service Bulletin/Repair Instructions

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.

25KWD 25PBD

Service Campaign

Additional US chassis have been added, along with additional Canadian chassis under identical safety recall 26PACB.

99-052

Service Bulletin/Repair Instructions

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.

26PACA

Service Bulletin/Repair Instructions

​Updated cross shaft and bearing installation steps have been added to the repair procedures.

46-028

Service Campaign

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.

E339

Emissions

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.

E340

Emissions

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.

E326

Emissions

EPA17-24 MX Fuel Injector Connector - This bulletin has been revised to include all EPA17-24 and CARB24 PACCAR MX engines.

15-034

Service Campaign

Battery Electric Vehicle (BEV) de-energizing and re-energizing procedures have been added to the bulletin for Peterbilt Model 520 BEV.

46-024

Service Bulletin/Repair Instructions

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

Service Bulletin/Repair Instructions

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.

01-090

Service Bulletin/Repair Instructions

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.

46-019

Service Bulletin/Repair Instructions

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.

Reading this report

Complaint counts are reports filed with NHTSA, not failure rates. A common model collects more of them than a rare one that breaks more often.

2026 Peterbilt 520 Service Bulletins: 16 bulletins | CarFathom