Cummins rolls out updated DEF inducement calibrations under EPA guidance
Cummins says tens of thousands of engines have already received updated diesel exhaust fluid calibrations that give operators more time before power or speed reductions.
- August 2025
- Tens of thousands
- July 6, 2026
What Happened
Cummins says it continues to support the U.S. Environmental Protection Agency's effort to reduce unnecessary impacts on equipment operators through updated diesel exhaust fluid (DEF) inducement calibrations, while maintaining emissions compliance, product performance and customer experience. The company says it remains on track with implementation of the EPA's August 2025 guidance across applicable on-highway and non-road products. Tens of thousands of engines have already received the updated calibrations. Those calibrations give operators more time to address certain DEF and selective catalytic reduction (SCR) system issues before engine power or speed reductions occur, which Cummins says helps minimize unnecessary equipment downtime.
The EPA issues guidance on DEF inducement calibrations that Cummins is implementing across applicable on-highway and non-road products.
Cummins publishes an earlier announcement on the topic, which it points customers to for additional information.
Cummins says tens of thousands of engines have already received updated calibrations and that it remains on track with implementation.
“We appreciate EPA's continued engagement with industry stakeholders and its focus on addressing customer concerns while maintaining emissions requirements. Cummins remains committed to supporting our customers with practical solutions that improve equipment availability and help them get their jobs done.”
Tens of thousands
Cummins says updated DEF inducement calibrations have reached that many engines so far, across applicable on-highway and non-road products.
For non-road customers in particular, Cummins says the updated guidance provides greater operational flexibility while recognizing the diverse and demanding applications in which Cummins-powered equipment operates. Cummins says it continues to work with the EPA and industry stakeholders as the agency considers future requirements. DEF remains a requirement for proper emissions system operation, and emissions compliance requirements remain in place. Customers are encouraged to contact their local Cummins distributor or dealer to learn more about available calibration updates.
Why this matters
The update is aimed at operators of Cummins-powered on-highway trucks and non-road equipment, who stand to lose less working time to certain DEF and SCR system issues before a derate kicks in. Cummins says the recalibrations keep engines emissions-compliant, and it stresses that DEF and emissions compliance requirements remain in place.
Terms in This Story
- DEF
- Diesel exhaust fluid, a fluid used in diesel emissions systems; Cummins notes it remains a requirement for proper emissions system operation.
- SCR
- Selective catalytic reduction, an emissions-control system on diesel engines that works together with diesel exhaust fluid.
- inducement calibrations
- Engine software settings that determine when a power or speed reduction is triggered to prompt the operator to address an emissions-system problem.
Summarised from the linked release; details can be imperfect — always verify against the original source.