Paccar will offer updated software for MX-11 and MX-13 engines that raises EPA DEF inducement speed from 5 mph to 25 mph and extends fault correction timelines. The calibration update will be factory-installed on trucks built after July 20 and available at dealerships for models from 2018 onward.
Paccar’s calibration update for MX-11 and MX-13 engines aligns with EPA’s revised DEF guidance by increasing final inducement speed from 5 mph to 25 mph and extending the allowable time to address emissions system issues before triggering derate.
Trucks manufactured after July 20 will ship with the new software pre-installed at the factory, while models built since 2018 can receive the update at Kenworth and Peterbilt dealerships, with full deployment across production and in‐service fleets through 2026.
The software enhancements aim to reduce unnecessary downtime and improve operational flexibility for carriers while ensuring continued compliance with EPA emissions standards, mirroring similar updates from Cummins for over 1.5 million engines and initiatives by other OEMs.
