2021 Kenworth T800B TSBs

When troubleshooting Cummins X15 fault codes 555 or 556, follow this additional testing, inspection, and documentation procedure to help identify the root cause of dusted engines. This is not a stand-alone process but must be used alongside Cummins troubleshooting steps. Cummins Quickserve will reference this bulletin for fault codes 555 or 556.

that had a previously failed DEF sensor and with DEF sensor software disabled due to industry DEF sensor shortages will now be able to receive a replacement DEF sensor, DEF tank heater coolant control valve, and re-enabled DEF diagnostic software. Please note that chassis equipped with PACCAR PX engines will be eligible for this repair at a future date when software is available.

This is a one-time reimbursement. Only customers who have received E290 injector cleaning qualify for this reimbursement. See bulletin for limits and purchase tracking requirements.

Broken oil valve tabs can cause oil flow obstruction to critical engine parts, resulting in serious engine damage. Customers that do not receive this repair may be responsible for progressive engine damage caused by broken oil bypass valve tabs.

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.

provide warrantable repair guidance. Oil leaks, if not repaired, can lead to severe engine damage.

to identify which of these engines are in a chassis.

This is not a stand-alone procedure. Cummins Quickserve troubleshooting will specify the use of these procedures while troubleshooting specific fault codes.

EPA2021 injector cleaning is referenced in RMI for certain injector faults. Complete the procedures in E290. Refer to E300 for in-tank additive information

EPA2021 injector cleaning is referenced in RMI for certain injector faults. Complete the procedures in E290. Refer to E300 for in-tank additive information

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.

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.

Additional diagnostics are available to correctly determine and repair the root cause of the issue.

appropriate tests for battery warranty are performed in order to prevent battery warranty claims filed with incorrect or incomplete information.

Parts will be shipped to dealers.

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.

Washer pumps may fail to spray due to a clogged filter.

On certain Kenworth model years 2018 through 2024 C500/T660/T800/W900 trucks with Sears Atlas 70 or 80 series seats, a spacer was installed on the seatbelt mounting assembly. In a severe collision, the ICP bar may fail, increasing the risk of injury.

Sears Atlas 70 or 80 series seats, an additional spacer was installed on the seatbelt mounting assembly. In a severe collision, the ICP bar may fail allowing the seatbelt to slip, increasing the risk of injury. This bulletin will be updated when repair parts and procedures become available.

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."

requirements per FMVSS/CMVSS 121 Air Brake Systems. This bulletin will be updated when repair parts and procedures are available.

steering knuckle may fail, increasing the risk of a crash or injury. Repair information will be added when a repair procedure and parts are available.

Parts will be shipped to dealers.

(LCA) fault codes leading to possible LCA hardware replacement.