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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

Bulletins, newest first
42-0702026-10-17. Service bulletin. UNKNOWN OR OTHER. Due to supplier constraints, an authorized aftermarket surge tank has been made available.
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."
24KWL/PBL2026-08-20. Service bulletin. FORWARD COLLISION AVOIDANCE: WARNINGS. The verbiage in the Introduction section has been updated.
24PBL2025-02-05. Service bulletin. FORWARD COLLISION AVOIDANCE: WARNINGS; UNKNOWN OR OTHER; ELECTRICAL SYSTEM. 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 numbers are not yet available. This bulletin will be updated when software update procedures are available for these chassis. Safety Recall publish date: 1/10/25
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.
16-0442024-08-02. Service bulletin. SUSPENSION. 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 them unable to inflate. Fix-as-fail start date is 07/30/2024.
R21052024-03-04. Service bulletin. ELECTRICAL SYSTEM; STEERING:COLUMN. Peterbilt has determined that certain model year 2021, pre-production chassis are eligible to have specific parts updated to production level.
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.
14-0432022-10-05. Service bulletin. SUSPENSION. Fix-As-Fail On certain chassis with Low Air Leaf Suspension or Low-Low Air Leaf Suspension, the Height Control Valve (HCV) arm may be rubbing on other components when the bend in the arm is facing outboard. Flipping the bend in the HCV arm inboard prevents the rub.
13-0602022-09-06. Service bulletin. SERVICE BRAKES. The service information for Bendix Air Dryer maintenance is being updated to include new procedures.
13-0572022-04-05. Service bulletin. EQUIPMENT; SERVICE BRAKES, AIR; EQUIPMENT ADAPTIVE/MOBILITY; SERVICE BRAKES, HYDRAULIC. Fix-As-Fail – A hill start assist (HSA) valve plumbing revision eliminates ice buildup in the HSA valve exhaust in cold weather.
51-0132022-03-04. Service bulletin. EQUIPMENT. Due to major data carriers phasing out 3G networks, chassis currently utilizing first generation Peoplenet Mobile Gateway (PMG001) will experience severe 3G service degradation as early as January of 2022. Chassis currently utilizing 3G antennas as a primary antenna may experience this degradation.
13-0582022-01-06. Service bulletin. ELECTRONIC STABILITY CONTROL:AUTOMATIC (ASC). Non-Safety Campaign – Certain model 337 and 348 medium duty chassis were built with the ABS module installed incorrectly
E2822022-01-06. 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.
43-0712021-10-05. Service bulletin. FUEL SYSTEM, DIESEL. Fix-As-Fail – Due to undersupply issues, only a limited supply of Diesel Exhaust Fluid (DEF) sensors are available. As a temporary solution, after PACCAR confirms a DEF sensor is not available, a temporary software update will allow a vehicle to continue operation with a failed DEF sensor by disabling the DEF sensor diagnostics.
02-1682021-10-05. Service bulletin. STRUCTURE. Information Only - Rear axle Quarter Fenders with less than two inches of clearance between the top of the quarter fender and the bottom of the trailer/equipment are susceptible to damage. The lack of clearance could result in cracked/broken quarter fenders or complete separation if undetected or un-remedied.
21-PBD2021-07-06. Service bulletin. FUEL SYSTEM, GASOLINE. Safety Recall – Cummins Fuel Rail Leak – NHTSA ID: 21V391 / TC: 2021-323, Cummins Recall: C2423. Cummins PX9 and ISX12 fuel rails may leak around a sealing washer, potentially resulting in fuel leaks. Undetected prolonged diesel fuel spray in the presence of an ignition source may increase the risk of fire.
15-0292021-06-02. Service bulletin. STEERING. Information Only - Power steering reservoir cap may separate during removal when it is pulled upward instead of twisted.
02-1602021-03-10. Service bulletin. VISIBILITY; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; VISIBILITY:WINDSHIELD WIPER/WASHER. Information Only – Windshield washer pumps have a high No Trouble Found rate. Washer pumps may fail to spray due to a clogged filter.
116-12021-02-01. Service bulletin. EQUIPMENT. SmartNav 2.0 Hardware retrofit for quality validation and vehicle validation units.
13-0552020-11-05. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT; SERVICE BRAKES, AIR. Fix as Fail: Peterbilt has introduced an improved mounting bracket for low mount air tanks for vehicles built between January 01, 2017 and July 06, 2020. Torsional vibration may stress the currently-installed brackets and cause them to fail near the bottom of the frame rail.
32-0152020-07-03. Service bulletin. ELECTRICAL SYSTEM. Information Only: This bulletin provides dealers with a battery warranty quick reference guide to ensure the appropriate tests for battery warranty are performed in order to prevent battery warranty claims filed with incorrect or incomplete information.
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.

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