2020 Peterbilt 337 TSBs
30 Technical Service Bulletins across 13 categories
Categories
Engine
6 bulletinsInfo Only Unnecessary starter replacements can result from customer complaints regarding engine starting issues.
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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.
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.
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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.
Info Only - PACCAR is introducing Over-the-Air (OTA) software updates for engine MY17 and newer chassis equipped with...
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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.
Fix-As-Fail On certain chassis with Low Air Leaf Suspension or Low-Low Air Leaf Suspension, the Height Control Valve...
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(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.
Fix-As-Fail A hill start assist (HSA) valve plumbing revision eliminates ice buildup in the HSA valve exhaust in cold...
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weather.
Fix-As-Fail - Composite fittings used in the cooling system may crack, resulting in coolant leaks.
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Brass fittings are available to replace the composite fittings.
Electrical
6 bulletinsFix As Fail Chassis that were manufactured with certain battery cable routing brackets may experience rubbing or...
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chafing of the battery cables.
Fix-As-Fail Due to undersupply issues, only a limited supply of Diesel Exhaust Fluid (DEF) sensors are available.
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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.
Safety Recall Cummins Fuel Rail Leak NHTSA ID: 21V391 / TC: 2021-323, Cummins Recall: C2423.Cummins PX9 and ISX12 fuel...
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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.
Information Only: This bulletin provides dealers with a battery warranty quick reference guide to ensure the...
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appropriate tests for battery warranty are performed in order to prevent battery warranty claims filed with incorrect or incomplete information.
Fix as Fail: For all conventional models, except 387/587, equipped with Side-of-Cab (SOC) exhaust and built from...
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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.
Information Only: Proper jump-starting voltage will eliminate high voltage related issues and equipment damage.
Other
3 bulletins"Kenworth: Dealers should check the chassis list and SIR weekly for VIN changes.
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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."
Information only: In 2020, Peterbilt and Kenworth began using the same M10, M12, M16, and M20 frame fasteners on all vehicles.
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Torque specifications for these fasteners are different from previous fasteners.
Fix-As-Fail: Two separate causes have been identified as root cause of intermittent low coolant indicator illumination.
Software & Calibration
3 bulletinsThe verbiage in the Introduction section has been updated.
The service information for Bendix Air Dryer maintenance is being updated to include new procedures.
Information Only - Vehicles built with NAMUX software from 2013 to present may experience accuracy issues with the tachometer.
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The issue can be temporarily resolved using any one of the included procedures.
Body & Paint
2 bulletinsInformation Only - Rear axle Quarter Fenders with less than two inches of clearance between the top of the quarter...
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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.
Information Only Windshield washer pumps have a high No Trouble Found rate.
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Washer pumps may fail to spray due to a clogged filter.
Brakes
2 bulletinsFix-As-Fail - Bendix New-Gen Lightweight Steer Axle Drum Brake Spider Cracking
Information: Chassis built after 01/11/2016 with hydraulic brakes were provided with a jumper harness in the glove box...
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or tool box that is required when programming the ABS. If this harness is no longer in the vehicle, order from PACCAR Parts.
Pre-Delivery & Maintenance
2 bulletinsInformation only: Hendrickson Softek front axle maintenance intervals and requirements.
Information Only This bulletin provides information about the California Air Resources Board (CARB) Periodic Smoke...
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Inspection Program (PSIP) and Heavy Duty Vehicle Inspection Program (HDVIP).
Fuel System
1 bulletinDue to major data carriers phasing out 3G networks, chassis currently utilizing first generation Peoplenet Mobile...
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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.
Transmission
1 bulletinFix-as-Fail: Radio does not mute when truck with auto trans is placed in reverse.
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Software flash resolves issue.
Infotainment
1 bulletinSmartNav 2.0 Hardware retrofit for quality validation and vehicle validation units.
Lighting
1 bulletinFix as Fail: Peterbilt has introduced an improved mounting bracket for low mount air tanks for vehicles built between...
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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.
HVAC & Climate
1 bulletinInformation Only: This bulletin provides guidance for repairing an air-conditioning system after internal failure of the...
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A/C compressor.
Steering
1 bulletinSafety Recall: Defectective lower hsaft to u-joint yoke in non-telescoping steering columns due to supplier weld not...
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creating enough penetration and can crack, which could lead to a loss of steering and increase risk of crash or injury. Resolution is to inspect for defective identified manufacturing lot and replace steering column if determined defective.