2021 Peterbilt 520 technical service bulletins
58 technical service bulletins and manufacturer communications cover the 2021 Peterbilt 520, including 2 warranty extensions.
Bulletins tell dealers how to fix known problems. A warranty extension means the manufacturer pays for that repair for longer.
- KW & PB 14 fuel injector part numbers (seven for MX-11 and seven for MX-13 engines) have been added to...
- 7/700 Service Agreement
- This optional software update is expected to be available after 10/30/2026 for chassis equipped with EMY...
- An upgraded power steering pump is available for certain Model 520 chassis with a RHSU or dual steering...
- Kenworth: Dealers should check the chassis list and SIR weekly for VIN changes
- The procedure has been updated to include additional steps for verifying the software level on the vehicle...
- The verbiage in the Introduction section has been updated.
- This optional software update is now available for chassis equipped with EMY 2021B-2023 PACCAR MX-11 and...
- The Condition, Chassis Affected, Service Action, Warranty, and Procedure sections have been updated to...
- The software is not yet available
- Additional US chassis have been added, along with additional Canadian chassis under identical safety...
- An optional software update will be available on 07/06/2026 for chassis equipped with EMY 2021B-2023PACCAR...
- KW: A new recommended repair has been added to verify the software level and close the campaign in SIR.The...
- Updated the point of contact for sourcing the MX Engine Overlay Harness Kits
- Certain Peterbilt Model 520 BEV chassis with an Accelera Power Control and Accessory System (PCAS) were...
- EPA17-24 mx
- Repair procedures and warranty information for model 520EV are now available
- Repair procedures and warranty information for model 520EV are now available
- Newly designed fuel injectors are available for EPA2021 compliant PACCAR MX-series engines to optimize...
- 5/29/2025: A new Ethernet Multiplexed Architecture (EMUX) Service Tool Kit service manual (SM034-022) has...
- 4/29/2025
- As of 03/25/2025, this campaign has resumed
- Vehicles equipped with PACCAR MX engines with Engine Software Version NA202 or NA206 may display a dash...
- Certain Peterbilt 579EV and 520EV Battery Electric Vehicles were built prior to the availability of...
- Safety Recall Updated software and procedures are now available
- Some 579EV and 520EV BEV trucks may have loose or improperly torqued ESS gland nuts
- Info Only Unnecessary starter replacements can result from customer complaints regarding engine starting...
- Fix-as-fail
- Information Only Storage guideline procedures are now available for both Medium Duty and Heavy-Duty...
- Information Only New diagnostic tool is required to support PACCAR Ethernet Multiplexed Architecture...
- Fix As Fail The height control valve (HCV) rod on vehicles with low air leaf suspensions is prone to...
- Updated procedures and SRT time to include Fuel Filter replacement during cleaning process
- A software fix for model 520EV that are not equipped with ESP (Stability Control) is now available
- Incorrect fuel filter drain and replacement procedures on EPA21 MX-11 and MX-13 engines can result in the...
- Quality and Volume Validation vehicles built for the 520 VMUX program between July 2019 and December 2020...
- PACCAR will reimburse customers for the local purchase of in-tank fuel additive for EPA2021 compliant MX...
- Fix-as-fail –
- Info Only
- The service information for Bendix Air Dryer maintenance is being updated to include new procedures.
- Info Only – Certain 520 model chassis built between 2014 and 2021, and equipped with the Red Dot HVAC...
- Information Only
- This bulletin provides information on the EPA21 MX fuel injector cleaning procedure and includes suggested...
- Fix-As-Requested
- Information Only – New Level 1 required tools are available to support MY21B MX engines.
- Due to major data carriers phasing out 3G networks, chassis currently utilizing first generation Peoplenet...
- Information Only: Due to differences between the PACCAR MX-11 or MX-13 2021A and 2021B engines,...
- Non-Safety Campaign: Certain DC tools were incorrectly calibrated
- Safety Recall – Certain Model 520 trucks may have been built without a quick release (QR) valve
- Fix-As-Fail – Due to undersupply issues, only a limited supply of Diesel Exhaust Fluid (DEF) sensors are...
- Safety Recall
- Safety Recall â Cummins Fuel Rail Leak â the federal safety agency ID: 21V391 / TC: 2021-323, Cummins...
- Information Only
- The current chassis harness connector contains a wire that is no longer necessary with the latest...
- Information Only – Windshield washer pumps have a high No Trouble Found rate
- Fix as Fail: Peterbilt has introduced an improved mounting bracket for low mount air tanks for vehicles...
- Electrical system
- Fix as Fail: For all conventional models, except 387/587, equipped with Side-of-Cab (“SOC”) exhaust and...
- Information Only:
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