Diesel Ford Lineup Will Be Impacted BY EPA DEF Derating Fix

Under President Donald Trump, the Environmental Protection Agency (EPA) has been working to roll back things like greenhouse gas standards for light-, medium-, and heavy-duty vehicles and heavy-duty engines, eliminate fines for Corporate Average Fuel Economy (CAFE) violations, and even get rid of automatic engine start-stop, moves that are aimed at reducing complexity and costs. Ford CEO Jim Farley recently praised these changes for those very same reasons, and now, the automaker will be impacted by yet another revision.

EPA Administrator Lee Zeldin has announced new guidance directing engine and equipment manufacturers to revise diesel exhaust fluid (DEF) system software in vehicles, with the intentions of preventing sudden shutdowns – which gives operators more time to repair faults without impacting safety or productivity. Currently, when DEF runs out or a sensor fails, those systems can force a vehicle to drastically reduce its speed or even become inoperable. The purpose of this was to ensure compliance with EPA’s Tier 4 Emissions Standards, but according to Zeldin, it has instead caused frustrations, delays, and economic hardship for those that use diesel vehicles like ones produced by Ford.

“We have heard loud and clear from small businesses across the United States that the current DEF system is unacceptable,” Zeldin said. “It is unacceptable that farmers, truckers, construction workers, and many other small businesses continually experience failures of diesel-powered equipment when they need it most – costing millions of dollars in lost productivity. Today, we are responding to those concerns by calling on manufacturers to take action to update their software and eliminate the unnecessary sudden loss of power and frustrating shutdowns that too many Americans have experienced.”

Since 2010, most on-road diesel trucks and other types of non-road equipment such as tractors and construction machinery have used selective catalytic reduction (SCR) systems that inject DEF into exhaust streams to reduce nitrous oxide (NOx) emissions. Now, starting with the 2027 model year, EPA requirements will change to state that new on-road diesel trucks must be engineered in a way that avoids sudden and severe power loss if they run out of DEF.

Additionally, existing diesel vehicles like those made by Ford will receive software changes to prevent this from happening, too. The EPA notes that these changes were developed in conjunction with manufacturers, and as such, it won’t be requiring separate approvals beyond this guidance to simplify the changes and ensure they’re made in a timely manner.