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Service bulletins for the 2020 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.

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

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Only bulletins with component: Engine are shown. Show all

Bulletins, newest first
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."
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.
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."
E3262026-05-06. Emissions. ENGINE; ELECTRICAL SYSTEM. EPA17-24 MX Fuel Injector Connector - This bulletin has been revised to include all EPA17-24 and CARB24 PACCAR MX engines.
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.
7-7002024-11-05. Warranty extension. POWER TRAIN; ENGINE. 7/700 Service Agreement - Letter Only.
45-0642022-11-02. Service bulletin. ENGINE AND ENGINE COOLING. Info Only - PACCAR is introducing Over-the-Air (OTA) software updates for engine MY17 and newer chassis equipped with Cummins X15, X12, ISX12, ISX12N, L9N, PX-7, and PX-9 engines The technology will leverage the existing Remote Diagnostic cs hardware to deliver secure software updates remotely. This will reduce downtime and save on maintenance costs for eligible vehicles.
R21032022-02-04. Service bulletin. ENGINE AND ENGINE COOLING. Retrofit - The emissions exemption will be expiring on 5/15/2022 for certain pre-production vehicles equipped with PACCAR MX-11 and MX-13 EPA 2021 Emissions engines. Production-level components are now available to make these vehicles compliant.
45-0622021-07-06. Service bulletin. ENGINE AND ENGINE COOLING. Fix-As-Fail – PX9 oil pan may leak due to improper hardware. Revised hardware will resolve the leak.
43-0672020-07-03. Service bulletin. STRUCTURE; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM. Fix as Fail: For all conventional models, except 387/587, equipped with Side-of-Cab (“SOC”) exhaust and built from 03/6/2006 to 1/20/2020, the clamps that secure the SOC exhaust stacks may not be tightened properly. This may allow the exhaust stack to rotate and contact the cab or sleeper.
01-0752019-12-04. Service bulletin. ENGINE AND ENGINE COOLING. Information Only: This bulletin provides guidance for repairing an air-conditioning system after internal failure of the A/C compressor.
TIB43-0622019-10-04. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM. Information Only – This bulletin provides information about the California Air Resources Board (CARB) Periodic Smoke Inspection Program (PSIP) and Heavy Duty Vehicle Inspection Program (HDVIP).
42-0562019-09-05. Service bulletin. ENGINE AND ENGINE COOLING. Fix-As-Fail -“ Composite fittings used in the cooling system may crack, resulting in coolant leaks. Brass fittings are available to replace the composite fittings.
42-0582019-09-05. Service bulletin. ENGINE AND ENGINE COOLING. Fix-As-Fail: Two separate causes have been identified as root cause of intermittent low coolant indicator illumination.

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