Volvo, Mack Expand DEF Software Updates for Heavy-Duty Trucks

Volvo Trucks and Mack Trucks are rolling out updated DEF software that gives drivers more time to repair emissions system issues before engine derates and speed restrictions take effect.

Volvo Trucks North America and Mack Trucks have announced updated diesel exhaust fluid (DEF) inducement software designed to give fleets and drivers more time to address emissions system issues before engine performance restrictions take effect.

The announcements follow similar updates from other major truck manufacturers and come as the U.S. Environmental Protection Agency (EPA) considers changes to federal emissions regulations affecting newly manufactured heavy-duty trucks.

Software Updates Extend Repair Window

According to Volvo Trucks and Mack Trucks, the updated software delays DEF-related engine derates and vehicle speed restrictions, allowing drivers additional time to reach a repair facility when emissions system issues occur.

The companies said the updates are intended to reduce unplanned downtime while maintaining emissions compliance and improving operational flexibility for fleets.

“By extending the repair window and increasing the final inducement speed, we are helping drivers keep their trucks on the road and safely reach a service location, reducing the risk of unexpected downtime and supporting the uptime and productivity our customers depend on every day,” said Peter Voorhoeve, president of Volvo Trucks North America.

Rollout Underway Across Multiple Models

Volvo said it has been producing trucks equipped with the updated software since May 2026 on vehicles powered by its D13 VGT and D13TC engines. Many recently manufactured trucks have already received the update through remote software downloads.

Mack has also begun installing the software on new Anthem and Pioneer models equipped with MP13 engines. The company expects the update to be available for all 2024 and newer Mack trucks by the end of the summer, with plans to extend the software to all eligible post-2010 models by the end of 2027.

Jonathan Randall, president of Mack Trucks North America, said the company remains focused on providing customers with solutions that support both regulatory compliance and day-to-day operations.

Industry Responds to Proposed EPA Rule Changes

Volvo Group’s announcement follows similar software updates introduced by Daimler Truck North America and Paccar as truck manufacturers respond to the EPA’s proposed emissions rule.

In June, the EPA proposed eliminating DEF-related engine derates and vehicle speed restrictions on newly manufactured heavy-duty trucks while maintaining emissions standards. If finalized, the proposal would change how manufacturers manage emissions system faults on future vehicles.

For fleets operating existing trucks, manufacturers say the new software is intended to reduce disruptions by allowing more time to schedule repairs before performance limitations are activated.