Daimler Truck North America (DTNA) is rolling out updated Diesel Exhaust Fluid (DEF) inducement software across its Detroit engine platform, a move the company says will help reduce unplanned downtime while maintaining emissions compliance.
The updated software is already being installed on new Freightliner and Western Star trucks equipped with Detroit engines. DTNA also began deploying the update to approximately 330,000 vehicles already in service in February 2026.
The rollout covers DD15 engines from model years 2021 through 2025 and DD13 engines from model years 2022 through 2025, with installations continuing throughout the year.
The software changes follow revised guidance issued by the US Environmental Protection Agency (EPA) in August 2025 regarding DEF inducement strategies.
DEF inducements are designed to ensure emissions systems remain operational by reducing vehicle speed and power when issues such as low-DEF levels or Selective Catalytic Reduction (SCR) system performance problems are detected. Drivers are then prompted to address the issue through actions such as refilling DEF, repairing components, replacing sensors, or performing regeneration procedures.
Under the revised guidance, trucks affected by component-related emissions system issues will have additional time before reaching final inducement. The final inducement speed limit has also been increased from five to 25 mph.
According to DTNA, the changes are intended to give operators more flexibility to schedule repairs while reducing unnecessary operational interruptions. The company noted that inducement logic related to low-DEF tank levels remains unchanged.
“For too long, small businesses like farmers, truckers, and construction workers have borne the cost of unreliable DEF systems through expensive repairs and needless downtime. This is why the SBA has been calling on OEMs to implement recent EPA guidance,” commented Kelly Loeffler, Administrator US Small Business Administration (SBA).
Loeffler continued: “The SBA welcomes Daimler Truck North America’s decision to equip vehicles with updated DEF inducement software, a common-sense step that gives operators greater reliability while reducing costs. This is exactly the kind of relief that the hardest working Americans deserve.”
DTNA emphasized that emissions compliance requirements remain in place and that vehicles must still be repaired to maintain environmental standards. SCR systems will continue using DEF to convert nitrogen oxides (NOx) into nitrogen and water, helping vehicles meet EPA emissions regulations.
Daimler Truck North America traces its roots to 1942 and is headquartered in Portland, Oregon. The company manufactures Freightliner and Western Star trucks, along with Detroit engines and related powertrain components, serving customers across the North American commercial vehicle market.
For more information, visit www.daimlertrucknorthamerica.com.