EPA announces DEF-related sudden shutdown ‘fix’

U.S. Environmental Protection Agency (EPA) Administrator Lee Zeldin announced new action yesterday to protect U.S. diesel equipment operators from sudden speed and power losses caused by diesel exhaust fluid (DEF) systems. The EPA issued guidance urging engine and equipment manufacturers to revise DEF system software in existing vehicles and equipment to prevent sudden shutdowns, giving operators more time to repair faults without impacting productivity or safety.

“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,” said Zeldin. “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.”

Starting with model year 2027, EPA requirements state that all new diesel on-road trucks must be engineered to avoid sudden and severe power loss after running out of DEF. To fix the problem for vehicles already in use, EPA’s new guidance, developed in collaboration with manufacturers, will work to ensure that the necessary software changes can be made on the existing fleet. The EPA is not requiring separate approvals beyond that provided in its guidance to ensure that bureaucratic steps do not delay manufacturers’ ability to put solutions into the field.

The Engine Technology Forum (ETF) was quick to applaud the new guidance.

“EPA has heard from users of diesel trucks, tractors, and equipment and, working with manufacturers, has responded with these adjustments to improve operational performance while ensuring emissions integrity,” Executive Director Allen Schaeffer stated.

Maintaining the advanced emissions control systems in diesel-powered vehicles and equipment, he said, including the replenishment of DEF and being attentive to indicators and inducements within a certain timeframe, is key to ensuring emissions system integrity, uninterrupted performance and clean air benefits.

“EPA’s announcement,” he added, “provides new guidance that will allow manufacturers to adjust these systems to ensure that farmers, motor coach operators and truckers who all rely on diesel engines and equipment will be able to complete critical work with sufficient lead time for scheduling maintenance and repairs.”

EPA said it continues to be committed to protecting air quality and public health while ensuring that engine operators can depend on the equipment they need. EPA added that it will continue to work with all stakeholders to ensure practical, durable solutions that simultaneously support emissions reductions and reliable operations.