PORTLAND, Ore. (June 16, 2026) — Daimler Truck North America LLC (DTNA), the leading manufacturer of Class 6–8 commercial vehicles, announced that its new production Detroit engines will come factory-equipped with updated software reflecting the U.S. Environmental Protection Agency’s (EPA) revised guidance on Diesel Exhaust Fluid (DEF) inducements.

Model Year 2027 Freightliner and Western Star vehicles equipped with Detroit engines are already shipping with the updated software installed. In addition, software updates for approximately 330,000 in-service vehicles began in February 2026, covering DD15 engines (MY21–MY25) and DD13 engines (MY22–MY25). These updates will continue throughout 2026.

In August 2025, the EPA updated its guidance for vehicles from Model Years 2010–2026. Diesel Exhaust Fluid (DEF) inducements are built-in safeguards on trucks that ensure emissions systems work properly. If a vehicle operates without DEF or under conditions that reduce the performance of the Selective Catalytic Reduction (SCR) system, the truck automatically reduces speed and power. This slowdown “induces” the driver to correct the issue - typically by refilling the DEF tank, repairing faulty sensors or components, or performing a regeneration cycle - protecting air quality while keeping the vehicle compliant with environmental standards.

SCR technology uses DEF to convert nitrogen oxides (NOx) exhaust into nitrogen and water. This process reduces NOx emissions and enables trucks to meet EPA standards while maintaining performance.

Under the new guidance, final inducements have increased their speed limit from 5 mph to 25 mph, and the time to final inducements related to component failures has been extended. This change gives operators more time to repair faults without compromising productivity or safety. While the extended timeframe allows fleets to avoid roadside disruptions, emissions compliance remains mandatory, and vehicles must still be repaired to ensure environmental standards are met. The logic to trigger final inducements related to DEF tank level remains unchanged.

This update reflects Daimler Truck North America’s commitment to combining regulatory compliance with innovation. By integrating the EPA’s revised inducement guidance into its products, the company supports fleet sustainability goals and ensures customers can operate efficiently while meeting the highest environmental standards. Daimler Truck North America has also informed its dealer network to ensure alignment and consistent implementation across the field.