January 31, 2026 Service bulletin

Procedure pictures updated for clarity

Kenworth technical service bulletin 45-070 for 2017-2026 Kenworth T680, 2017-2026 Peterbilt 579 and 2017-2025 Kenworth T800 and others.

Bulletin number: 45-070 (45-070)
Component: Engine
Summary: Procedure pictures updated for clarity. 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.

Owners of these vehicles have filed 9 complaints in the engine category.

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