The Environmental Protection Agency on Tuesday announced a "fix" to "protect American farmers, truckers, and other diesel equipment operators from sudden speed and power losses caused by diesel exhaust fluid (DEF) systems."
According to an EPA release, "EPA issued clear guidance urging engine and equipment manufacturers to revise DEF system software in existing vehicles and equipment to prevent these sudden shutdowns, giving operators more time to repair faults without impacting productivity or safety."
That guidance will require all new diesel on-road trucks starting in model year 2027 to be "engineered to avoid sudden and severe power loss after running out of DEF."
Additionally, the guidance states that vehicles already in use will undergo "the necessary software changes" to extend the timeline for engines derating due to DEF problems.
The EPA provided a chart showing derate timing for heavy duty trucks will be extended from a 5 mph limitation after just four hours' worth of a system fault to a three-stage derate:
- 15% torque reduction at 650 miles / 10 hours
- 30% torque reduction then at 4,200 miles / 80 hours
- and a final-stage derate to 25 mph at 8,400 miles / 160 hours
"In addition to providing certainty to manufacturers about how EPA wants this issue resolved, the agency is not requiring separate approvals beyond that provided in EPA’s guidance," the release said. "This ensures that bureaucratic steps do not delay manufacturers’ ability to put solutions into the field."
Administrator Lee Zeldin said the agency had “heard loud and clear from small businesses across the United States that the current DEF system is unacceptable. 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.”
Iowa Senator Jon Ernst added that “the previous arbitrary diesel exhaust fluid system guidelines severely hurt farmers, truckers, and small businesses that rely on diesel powered trucks. Not only will the new guidelines save family-run farms hundreds of millions every year, but it is also simply common sense."
[Related: How truck and engine OEs might approach EPA's new DEF-derate guidance]
The move came after the Trump administration targeted for repeal the EPA's Endangerment Finding which has allowed presidential administrations to regulate six greenhouse gases (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride) since 2009.
The EPA has completed almost a full 180 on greenhouse gas rules during the second Trump administration, leading to some delays and confusion among equipment manufacturers.
EPA on Tuesday said it "remains committed to protecting air quality and public health while ensuring that engine operators can depend on the equipment they need."
Additionally the agency "will continue to work with all stakeholders to ensure practical, durable solutions that simultaneously support emissions reductions and reliable operations," it said.
[Related: Cummins delays new X15 diesel amid regs uncertainty]
