2021 Peterbilt 337 problems, complaints & recalls
Safety recalls (2)
Electrical System:software 2024-12-09 · campaign 24V915000 · 220,764 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2021-2025 Peterbilt and Kenworth vehicles, equipped with Bendix EC80 Advanced Electronic Control Units (ECU). Please see the recall report for a complete list of models. Electrical noise and low signal to the power line carrier may cause the ECU to incorrectly process commands or stop functioning.
Risk: Safety systems that depend on the ECU (Automatic Traction Control, ABS, Electronic Stability Control, Active Cruise Control, and Collison Mitigation System) may not function properly or at all, increasing the risk of a crash.
Fix: Dealers will reprogram the ECU software, free of charge. Owner notification letters were mailed February 3, 2025. Owners may contact Kenworth's customer service at 1-425-828-5888 and Peterbilt's customer service at 1-940-591-4220. PACCAR's numbers for this recall are 24KWL and 24PBL.
Fuel System, Diesel:fuel Injection System:fuel Rail 2021-05-26 · campaign 21V391000 · 612 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2018-2021 Peterbilt 337, 348, 365, 367, 520, 567, Kenworth T270, T370, T440, T470, T800 and T880 vehicles. The sealing washer may not seat correctly in the pilot bore holes, allowing the high pressure fuel rail assembly to leak.
Risk: A fuel leak in the presence of an ignition source increases the risk of a fire.
Fix: Dealers will inspect the rail threads and fuel lines, and replace the rail as necessary, free of charge. Owners may contact PACCAR customer service at 1-425-828-5888 (Kenworth) or 1-940-591-4220 (Peterbilt). PACCAR's numbers for this recall are 21KWC and 21PBD.
Service bulletins (22)
Technical service bulletins are repair instructions manufacturers send dealers for known issues. Unlike recalls, the fix is not automatically free — but naming the bulletin at the service desk can save diagnosis time and support goodwill repairs.
Engine 2026-09-11 · P001 · Service Bulletin/Repair Instructions
"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."
Forward Collision Avoidance: Warnings 2026-08-13 · 24KWL/PBL · Service Bulletin/Repair Instructions
the verbiage in the introduction section has been updated.
Unknown Or Other 2025-01-10 · 24PBL · Service Bulletin/Repair Instructions
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 nu
Engine 2024-11-22 · 32-025 · Service Bulletin/Repair Instructions
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 warran
Suspension 2024-07-30 · 16-044 · Service Bulletin/Repair Instructions
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 th
Steering:column 2024-02-14 · R2105 · Service Bulletin/Repair Instructions
peterbilt has determined that certain model year 2021, pre-production chassis are eligible to have specific parts updated to production level.
Showing the 6 most recent of 22 bulletins. Search all of them free at nhtsa.gov.
What owners report
No detailed complaint narratives on file.
Excerpts of consumer complaints filed with NHTSA, lightly truncated. They are owner statements, not verified findings.