WASHINGTON – Today, at the White House Great American Agriculture Celebration, President Trump announced the U.S. Environmental Protection Agency (EPA) is removing the Diesel Exhaust Fluid (DEF) sensor requirement for all diesel equipment. This action aims to address concerns regarding DEF system failures, which have caused sudden speed losses and shutdowns impacting safety and productivity.
EPA’s fresh guidance, announced March 27, 2026, will provide immediate relief and is projected to save Americans $13.79 billion annually, with $4.4 billion of that benefiting farmers, according to the U.S. Modest Business Administration.
On February 3, 2026, EPA demanded critical data on DEF system failures from manufacturers accounting for over 80 percent of all DEF products. The agency has received data from 11 of 14 manufacturers and used preliminary findings to issue today’s guidance.
“Failing DEF systems are not an east coast or west coast or heartland issue. We see a nationwide disaster,” said EPA Administrator Lee Zeldin. “Americans are justified in being fed up with failing DEF system issues. Farmers and truckers should not be losing billions of dollars because of repair costs or days lost on the job.”
SBA Administrator Kelly Loeffler stated, “Today, by eliminating DEF mandates, the Trump Administration is taking yet another step to free up hardworking Americans to focus on the vital perform of feeding, clothing, building, and fueling our nation.”
EPA as well affirmed that approved NOx sensor-based software updates can be installed on existing engines without being considered illegal tampering, aligning with the agency’s February 2026 Right to Repair clarification guidance. This represents expected to reduce errors from traditional sensor technologies.
Previously, in August 2025, EPA issued guidance calling on manufacturers to revise DEF system software to reverse “deratements” impacting farmers and truckers. Manufacturers have begun making this improved software available, and EPA plans to propose a new rule removing all DEF deratements for new vehicles and engines.
EPA will continue reviewing data from manufacturers to identify further improvements to emission systems. The agency stated today’s announcement does not weaken emissions standards but aims to ensure they are met effectively.
For more information, please see EPA’s Diesel Exhaust Fluid page.
Frequently Asked Questions
What prompted the EPA to remove the DEF sensor requirement?
The EPA took this action in response to nationwide concerns from farmers, truckers, and other diesel equipment operators regarding DEF system failures that caused sudden speed losses and shutdowns.
How much money is this action expected to save?
This action is expected to save Americans $13.79 billion annually, including $4.4 billion for farmers.
What did the EPA do in February 2026 regarding DEF systems?
On February 3, 2026, the EPA demanded critical data on DEF system failures from manufacturers accounting for over 80 percent of all DEF products.
As the EPA continues to gather data and refine its approach, what further changes to diesel emission standards might we see in the coming years?