Vehicle report

2026 KENWORTH W990

Service bulletins

22 bulletins

Technical service bulletins are instructions a manufacturer sent its dealers about a known fault. They are not recalls and the work is usually not free, but they are the clearest signal of a problem the manufacturer already knows about.

P001

Service Bulletin/Repair Instructions

KW: The chassis list has been updated to include 1 chassis. The total chassis count is now 53. A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section. PB: The chassis list has been updated to include 8 chassis. The total chassis count is now 130. A link to the PACCAR Powertrain Prognostics Webcast has been added in the Links section.

43-089

Service Bulletin/Repair Instructions

This optional software update is expected to be available after 08/28/2026.

24KWC/24PBC

Service Bulletin/Repair Instructions

Updated Sheppard Steering Gear Classification Tool link in Inspection Procedure

41-029

Service Bulletin/Repair Instructions

Incorrect air filters may be inadvertently installed in certain chassis equipped with under-hood Donaldson air filter housings.

31-002

Service Bulletin/Repair Instructions

An installation guide is now available for temporary solar battery maintainers used on vehicles in dealer inventory. Using solar battery maintainers according to the attached guide can reduce instances of dead or undercharged batteries in stock vehicles at dealerships. Use of solar maintainers is considered a best practice for battery maintenance.

32-009

Service Bulletin/Repair Instructions

The battery care, maintenance, and charging guidelines have been updated to include Absorbent Glass Mat (AGM) battery information. Dealers are responsible for maintaining inventory trucks and on-shelf batteries.

99-052

Service Bulletin/Repair Instructions

There is an update to the Base Emissions Warranty Limits table [PR1.1]and general certification information in certain Engine Model Year (EMY) 2026 MX-11 and MX-13 Operator’s Manuals.

T024

Service Bulletin/Repair Instructions

KW & PB: New software is available for download. The DAVIE4 cache must be cleared before attempting to reprogram a chassis that is experiencing problems to ensure the latest version of software is installed. Follow all steps in the attached procedures before submitting a TCS case.

T-024

Service Bulletin/Repair Instructions

The repair procedure has been updated to include diagnostic steps.

R2601

Service Bulletin/Repair Instructions

Updated primary and/or secondary chassis modules for certain pre-production Kenworth chassis are now available for installation.

02-177

Service Bulletin/Repair Instructions

Troubleshooting procedures for 2.1m cab power windows are now available.

43-087

Service Bulletin/Repair Instructions

(KW) Certain T680 / T800 / T880 / W900 / W990 have updated GHG labels available for order and installation.

41-024

Service Bulletin/Repair Instructions

Procedures have been updated to include additional truck models in the service intervals table.

45-070

Service Bulletin/Repair Instructions

The attached procedures document has been updated with more detail and explanations. This is not a stand-alone procedure. Cummins Quickserve troubleshooting will specify the use of these procedures while troubleshooting specific fault codes.

14-034

Service Bulletin/Repair Instructions

Bogie Crossmember Torque Value Update - Procedure has been updated to correct torque values.

E326

Emissions

EPA17-24 MX Fuel Injector Connector - This bulletin has been revised to include all EPA17-24 and CARB24 PACCAR MX engines.

34-100

Service Campaign

Halogen Headlamp Operation -Activating the Flash to Pass system on certain [Kenworth / Peterbilt] vehicles may cause one headlamp to deactivate.

43-083

Service Bulletin/Repair Instructions

Exhaust Stack Isolators - Early wear of the polyurethane exhaust stack isolators may occur on certain Kenworth chassis due to excessive heat. Early wear of the polyurethane exhaust stack isolators may occur on certain Peterbilt chassis due to excessive heat.

12-001

Service Bulletin/Repair Instructions

Vehicles equipped with Watson & Chalin 20K AL2200 lift axles may have crossmember fasteners of incorrect grade.

43085

Service Bulletin/Repair Instructions

Certain vehicle model year 2026 T880 / W900 / W990 chassis have updated GHG labels available for order and installation.

25PACF

Service Bulletin/Repair Instructions

Parts and procedures are now available for all affected chassis equipped with Vehicle Electronic Control Unit (VECU) part number Q21-1157-013-011 / Q21-1157-013-013 / Q21-1157-002-002 / Q21-1157-004-004 / Q21-1157-006-006 / Q21-1157-009-009. See attached Parts Matrix for required parts per chassis.

27-011

Service Bulletin/Repair Instructions

A transmission control module (TCM) software update is now available for certain T680 / T880 / W900 / W990 chassis with Eaton Endurant transmissions running TCM software version 5516372, where the PTO fails to operate or engage. Please see the attached Eaton bulletin TAIB- 1021 in the Attachments section of this bulletin for complete details.

Reading this report

Complaint counts are reports filed with NHTSA, not failure rates. A common model collects more of them than a rare one that breaks more often.