Service bulletins for the 2021 Peterbilt 337
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.
23 on file from NHTSA, as of 2026-10-19.
By type
By component
Only bulletins with component: Engine are shown. Show all
| P001 | 2026-09-29. 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." |
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| 32-025 | 2024-12-03. 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. |
| 45-064 | 2022-11-02. 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. |
| E282 | 2022-01-06. Service bulletin. ENGINE AND ENGINE COOLING. Information Only: Due to differences between the PACCAR MX-11 or MX-13 2021A and 2021B engines, technicians must be able to identify which of these engines are in a chassis. |
| 43-067 | 2020-07-03. 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. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.