EPA Pushes Replacements for Faulty Urea Sensors in Diesel SCR Systems
The EPA indicates it will not deregulate DEF but encourages replacing unreliable urea quality sensors in diesel SCR systems with alternatives (such as NOx sensors) to verify DEF concentration. The agency notes that third parties can remove urea sensors if they install an effective replacement, though no emissions deletes are allowed. The move follows reports of high failure rates and ongoing cold-weather issues with DEF, and comes amid state-level interest in easing DEF requirements in harsh climates.