2021 Peterbilt 337 technical service bulletins

Bulletins tell dealers how to fix known problems. A warranty extension means the manufacturer pays for that repair for longer.

• Sep 11, 2026 Service bulletinKenworth: Dealers should check the chassis list and SIR weekly for VIN changes
• Aug 13, 2026 Service bulletinThe verbiage in the Introduction section has been updated.
• Jan 10, 2025 Service bulletinSafety Recall Updated software and procedures are now available
• Nov 22, 2024 Service bulletinInfo Only Unnecessary starter replacements can result from customer complaints regarding engine starting...
• Jul 30, 2024 Service bulletinFix As Fail The height control valve (HCV) rod on vehicles with low air leaf suspensions is prone to...
• Feb 14, 2024 Service bulletinElectrical system
• Oct 18, 2022 Service bulletinInfo Only
• Sep 9, 2022 Service bulletinFix-As-Fail On certain chassis with Low Air Leaf Suspension or Low-Low Air Leaf Suspension, the Height...
• Aug 3, 2022 Service bulletinThe service information for Bendix Air Dryer maintenance is being updated to include new procedures.
• Mar 3, 2022 Service bulletinFix-As-Fail – A hill start assist (HSA) valve plumbing revision eliminates ice buildup in the HSA valve...
• Feb 4, 2022 Service bulletinDue to major data carriers phasing out 3G networks, chassis currently utilizing first generation Peoplenet...
• Dec 17, 2021 Service bulletinInformation Only: Due to differences between the PACCAR MX-11 or MX-13 2021A and 2021B engines,...
• Dec 14, 2021 Service bulletinNon-Safety Campaign – Certain model 337 and 348 medium duty chassis were built with the ABS module...
• Sep 21, 2021 Service bulletinFix-As-Fail – Due to undersupply issues, only a limited supply of Diesel Exhaust Fluid (DEF) sensors are...
• Sep 20, 2021 Service bulletinInformation Only
• Jun 22, 2021 Service bulletinSafety Recall – Cummins Fuel Rail Leak – the federal safety agency ID: 21V391 / TC: 2021-323, Cummins...
• May 27, 2021 Service bulletinInformation Only
• Feb 10, 2021 Service bulletinInformation Only – Windshield washer pumps have a high No Trouble Found rate
• Oct 1, 2020 Service bulletinFix as Fail: Peterbilt has introduced an improved mounting bracket for low mount air tanks for vehicles...
• Jun 10, 2020 Service bulletinFix as Fail: For all conventional models, except 387/587, equipped with Side-of-Cab (“SOC”) exhaust and...
• Jun 8, 2020 Service bulletinInformation Only:
• Jul 13, 2016 Service bulletinSmartNav 2.0 Hardware retrofit for quality validation and vehicle validation units.