Kenworth Truck Company and Peterbilt Motors Company will implement updated software for vehicles equipped with Paccar MX-11 and Paccar MX-13 engines, reflecting revised U.S. Environmental Protection Agency’s (EPA) guidance on diesel exhaust fluid (DEF) inducements.

Trucks manufactured after July 20, 2026, will have the software installed at the factory. Trucks built after 2018 will be available for these software updates at Kenworth and Peterbilt dealerships.

What the Software Update Provides

In alignment with the EPA's guidance, these updates are designed to help Kenworth and Peterbilt customer improve reliability and reduce unnecessary disruptions to their operations by:

•Having the final inducement speed limit increased from 5 mph to 25 mph

•Extending the timeline from 4 to 160 hours for component-related or fluid-quality issues before reaching final inducement speed limit

How DEF Inducements are Safeguards

DEF inducements are safeguards that reduce vehicle speed and power when emissions system issues are detected. Common issues include low DEF levels or reduced selective catalytic reduction (SCR) system performance.

DEF inducements prompt drivers to correct the issue by refilling the DEF tank, repairing faulty sensors, or performing a system regeneration.

All MX-powered vehicles remain subject to EPA emissions requirements. Vehicles requiring repairs to emissions components must be serviced to maintain compliance.