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Service bulletins for the 2021 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.

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

By type

By component

Only bulletins with type: Service bulletin are shown. Show all

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."
24KWL/PBL2026-08-20. Service bulletin. FORWARD COLLISION AVOIDANCE: WARNINGS. The verbiage in the Introduction section has been updated.
43-0882026-08-20. Service bulletin. ENGINE. The procedure has been updated to include additional steps for verifying the software level on the vehicle electronic control unit (VECU2) and digital display (DD). Steps have also been added to the PACCAR Common Rail Injection 2 (PCI2) software verification.
43-0882026-07-23. Service bulletin. ENGINE. This optional software update is now available for chassis equipped with EMY 2021B-2023 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.
E3182026-07-22. Service bulletin. ENGINE. The Condition, Chassis Affected, Service Action, Warranty, and Procedure sections have been updated to include the latest prognostics bulletin verbiage. The Warranty section has also been updated to include Peterbilt specific SRT codes for filing cross-division repairs.
43-0882026-07-21. Service bulletin. ENGINE. "The software is not yet available. The bulletin will be updated when more information is available."
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."
R21032026-06-17. Service bulletin. ELECTRICAL SYSTEM; ENGINE. Updated the point of contact for sourcing the MX Engine Overlay Harness Kits. This retrofit should have been completed by 5/15/2022 per the Action section of the bulletin. However, trucks still open in SIR are still eligible for the repairs.
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.
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.
24PBL2025-02-05. Service bulletin. FORWARD COLLISION AVOIDANCE: WARNINGS; UNKNOWN OR OTHER; ELECTRICAL SYSTEM. Safety Recall Updated software and procedures are now available. 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
32-0252024-12-03. Service bulletin. ENGINE. Info Only Unnecessary starter replacements can result from customer complaints regarding engine starting issues. A new Starter Troubleshooting Guide has been created to provide a comprehensive list of starting system checks, which should reduce unnecessary starter replacements and associated warranty claims. Engine starting system warranty claims now require a completed Starter Checklist, a Battery Pack Midtronics Report, and a Cable Drop Midtronics Report. Claims filed without these documents may be denied.
46-0112024-12-02. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Some 579EV and 520EV BEV trucks may have loose or improperly torqued ESS gland nuts. This may cause an intermittent warning light on the dash display.
E2902024-10-05. Service bulletin. FUEL/PROPULSION SYSTEM. FIX-AS-FAIL Updated to include EPA2024 compliant engines. 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.
46-0142024-10-05. Service bulletin. UNKNOWN OR OTHER. Information Only Storage guideline procedures are now available for both Medium Duty and Heavy-Duty Battery Electric Vehicles.
16-0442024-08-02. Service bulletin. SUSPENSION. Fix As Fail The height control valve (HCV) rod on vehicles with low air leaf suspensions is prone to toggling over center during rough road conditions. With full suspension articulation, HCV bracket flexes and toggles over center the HCV linkage, which results in either deflated airbags or makes them unable to inflate. Fix-as-fail start date is 07/30/2024.
E2902023-12-02. Service bulletin. ENGINE AND ENGINE COOLING. Updated procedures and SRT time to include Fuel Filter replacement during cleaning process. Removed in-tank additive references.
46-0032023-11-10. Service bulletin. ELECTRONIC STABILITY CONTROL:AUTOMATIC (ASC). A software fix for model 520EV that are not equipped with ESP (Stability Control) is now available. The currently available soft ware, part number:SCM_1p5_BC_R5p00_003, will address issues caused by software version R5.00_002 that affect Peterbilt Model 520EV. The software update will correct the following issues: 1.) Power gauge displays axle RPM instead of power draw, 2.) Air conditioning compressor is inoperative below 10 mph (16 kmh) and over 40 mph (65 kmh), 3.) Low air and low coolant audible alarms (buzzers) are inoperative below 10 mph (16 kmh), and 4.) (520EV Only) Does not charge without ignition in on position.
E3062023-11-10. Service bulletin. FUEL SYSTEM, DIESEL. Incorrect fuel filter drain and replacement procedures on EPA21 MX-11 and MX-13 engines can result in the following: .Debris and contaminants introduced into the high-pressure fuel system. .Denial of warranty claims for injector and/or fuel system faults. .Misfire, rough running, engine knock, and other associated faults and symptoms. Correct fuel filter procedures are outlined in attached service documentation.
R23042023-08-03. Service bulletin. ELECTRICAL SYSTEM. Quality and Volume Validation vehicles built for the 520 VMUX program between July 2019 and December 2020 are eligible for a retrofit of the digital display to a production intent unit that features updated base software, secured hardware, and the ability to be updated with software released after February 2021.
E3002023-05-05. Service bulletin. ENGINE AND ENGINE COOLING. PACCAR will reimburse customers for the local purchase of in-tank fuel additive for EPA2021 compliant MX engines. This is a one-time reimbursement. Only customers who have received E290 injector cleaning qualify for this reimbursement. See bulletin for limits and purchase tracking requirements.

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