The U.S. Environmental Protection Agency, led by EPA Administrator Lee Zeldin, said it will no longer require Diesel Exhaust Fluid (DEF) urea quality sensors on diesel-powered equipment, while U.S. Representative Mike Collins (R-Ga.) introduced the Diesel Truck Liberation Act and U.S. Senator Cynthia Lummis (R-Wyo.) filed a Senate companion to repeal federal motor-vehicle emissions authority and anti-tampering laws.
The EPA move follows earlier actions: in August 2025 Zeldin advised manufacturers not to force limp modes for low DEF levels, and in January 2026 the U.S. Department of Justice said it would no longer pursue criminal charges for tampering with onboard diagnostics. In February the EPA said it was seeking to hold manufacturers accountable for unreliable DEF systems and considered eliminating emissions-related limp modes.
Together the EPA action and the Diesel Truck Liberation Act would further unwind emissions protections, with multiple federal agencies and lawmakers advancing measures to reduce regulatory constraints on diesel engines.
Manufacturers and engineers note that modern diesel emissions systems cut smoke and odor but can be complex and costly to repair, sometimes triggering limp modes or power derates; the EPA cited those reliability and consumer-impact concerns in its change to DEF sensor requirements.
Read the full article at theautopian.com.
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