DTNA Rolls Out DEF Derates Software Update

Daimler Truck North America has begun rolling out an optional software update for approximately 330,000 in-service Detroit-powered vehicles, including those with DD15 engines from model years 2021-2025 and DD13 engines from model years 2022-2025. The update revises diesel exhaust fluid inducement parameters, increasing the minimum speed before work must be carried out and extending timing for component-related issues. The revised parameters raise final-inducement speed limits to 25 mph from 5 mph. The update follows revised guidance from the Environmental Protection Agency in August and is set to continue throughout 2026. The software update is optional and must be carried out with an on-site hard plug-in using a diagnostic link. Freightliner and Western Star vehicles equipped with Detroit engines are already shipping with the updated software. The update is expected to provide relief to small businesses, such as farmers, truckers, and construction workers, who have borne the cost of unreliable DEF systems through expensive repairs and needless downtime. DTNA does not plan to remove DEF sensors from current vehicles, despite the EPA’s approval of a guidance update that will allow truck manufacturers to replace urea quality sensors with nitrogen oxide sensors.