Mack and Volvo are rolling out updated software for diesel exhaust fluid (DEF) inducement across new and existing truck models, with plans to extend the benefits to all eligible post-2010 model year vehicles by the end of 2027.

A DEF inducement is a built-in safeguard that reduces engine power and vehicle speed when the emissions system detects a fault, such as low DEF levels or the Selective Catalytic Reduction (SCR) system operating incorrectly. (Commonly called "derates.") SCR reduces the emission of NOx (nitrogen oxide) into the air using DEF.

New EPA guidelines essentially modify emissions regulations to extend final inducement speeds from 5 mph to 25 mph and increase the repair window from four hours up to 160 hours.

The updated software gives customers substantially more time to address DEF-related issues before the engine derates or the vehicle goes into reduced-speed inducement, helping improve uptime.

Cummins, Paccar, and Detroit previously announced similar software updates.

Mack DEF Software Updates

Mack began incorporating the updated software in May 2026 on Mack Pioneer and all-new Mack Anthem models equipped with the Mack MP13 engines. The company will have software updates available for all 2024 and newer vehicles by the end of the summer.

Mack is also broadening availability of changes outlined in the EPA’s guidance document to include all post-2014 vehicles by the second quarter of 2027.

By the end of 2027, owners of all eligible post-2010 Mack trucks that do not have remote software update capability will be able to receive the updated software through Mack dealers.

Volvo DEF Software Updates

All new Volvo trucks rolling off the assembly line now include updated DEF inducement software.

In addition to new production vehicles, Volvo Trucks is rolling out the updated software across in-service truck models, with availability continuing to expand throughout 2027.

Since May 2026, Volvo Trucks has been producing D13 VGT and D13 TC engines featuring the updated software in the all-new VNL and all-new VNR trucks.

Additionally, this updated software has been available in the aftermarket and has already been remotely downloaded into a large population of the new Volvo truck models.

Volvo Trucks will roll out remote software updates to legacy model year 2024 and newer vehicles by the end of the summer.

Volvo Trucks is also broadening availability of changes outlined in the EPA guidance document to include all post-2014 model year vehicles by the second quarter of 2027 and all eligible post-2010 model year vehicles by the end of 2027.

Truck models that do not have remote software update capability will be offered the updated software at their local Volvo Trucks dealerships.