EPA removes DEF sensor requirement in move to save truckers and farmers ‘countless hours of lost time’

The U.S. Environmental Protection Agency (EPA) announced a major move intended to save farmers, truckers, and other diesel equipment operators “billions of dollars in repairs and lost productivity.”

On March 27, 2026, the EPA announced new guidance to remove the Diesel Exhaust Fluid (DEF) sensor requirement for all diesel equipment in an action that officials say will save Americans “countless hours of lost time and productivity.”

The guidance was issued after a February 3, 2026, call from the EPA for manufacturers to submit data on DEF system failures.

“The preliminary review of the warranty data suggests that DEF sensor failures are a significant source of warranty claims and DEF-related inducement. Farmers and truck drivers should not have their vehicles stop working because a sensor isn’t working properly. EPA is taking immediate action on this new information. The agency’s new guidance makes clear that under existing regulations, manufacturers can stop inaccurate DEF system failures by removing traditional emission sensors, known as Urea Quality Sensors, and switching to nitrous oxide (NO_x) sensors,” the agency said.

The EPA also noted that approved NO_x sensor-based software updates can be installed on existing engines without being treated as illegal tampering under the Clean Air Act, under Right to Repair clarification guidance issued in February 2026.

The EPA’s action is expected to save farmers $4.4 billion a year and provide $13.79 billion a year of savings to Americans, according to the U.S. Small Business Administration (SBA).

“Today’s announcement does not weaken or remove emissions standards. Instead, it ensures that those standards are met in a way that actually works in the real world,” the EPA said.

EPA Administrator Lee Zeldin said that the action was taken in response to concerns from truckers and farmers regarding sudden speed losses and shutdowns caused by DEF system failures.

“Failing DEF systems are not an east coast or west coast or heartland issue; it is a nationwide disaster. I have heard from truck drivers, farmers, and many others complaining about DEF and pleading for a fix in all 50 states I visited during my first year as EPA Administrator,” said Zeldin. “Americans are justified in being fed up with failing DEF system issues. EPA understands this is a massive issue and has been doing everything in our statutory power to address this. Today, we take another step in furthering our work by removing DEF sensors. Farmers and truckers should not be losing billions of dollars because of repair costs or days lost on the job.” 

“Few small businesses have been hit harder by the Green New Scam than those who make up America’s great agriculture industry, where massive regulatory burdens have crushed family farms and driven up grocery costs,” said SBA Administrator Kelly Loeffler. “Today, by eliminating DEF mandates, the Trump Administration is taking yet another step to free up hardworking Americans to focus on the vital work of feeding, clothing, building, and fueling our nation. I applaud Administrator Zeldin for his leadership on this issue, and I look forward to our continued collaboration to cut red tape for small businesses across the U.S. food supply chain.”