PACCAR recently announced that updated software will be available for trucks equipped with PACCAR MX-11 and PACCAR MX-13 engines in response to revised EPA guidance regarding Diesel Exhaust Fluid (DEF) inducements. The changes are intended to give drivers and fleets more time to address certain emissions system issues before the truck enters its final speed-limited operating mode.

What Is Changing?

Beginning with trucks manufactured after July 20, 2026, the updated software will be installed at the factory on all Peterbilt models equipped with PACCAR MX-11 and MX-13 engines.

For Peterbilt trucks built in 2018 or later, the software update will also be available through authorized Peterbilt dealerships.

The update includes two significant improvements:

• The final inducement speed limit increases from 5 mph to 25 mph.
• The time before reaching the final inducement stage increases from 4 hours to 160 hours for component-related or DEF fluid-quality issues.

These changes provide drivers and fleet managers with significantly more flexibility to schedule service and complete deliveries before repairs are required.

What Are DEF Inducements?

Diesel Exhaust Fluid (DEF) inducements are built-in safeguards that help ensure heavy-duty diesel engines continue to meet federal emissions standards.

When the emissions system detects an issue—such as:

• Low DEF levels
• Poor DEF fluid quality
• Reduced Selective Catalytic Reduction (SCR) system performance
• Certain emissions component or sensor faults

the vehicle will gradually reduce engine performance or limit vehicle speed until the problem is corrected.

These safeguards encourage operators to refill the DEF tank, replace faulty components, or perform the necessary maintenance to restore proper emissions system operation.

Why This Matters

Under previous software calibrations, some emissions-related issues could result in the truck reaching its final 5 mph inducement within a relatively short period of time. That often created operational challenges for fleets trying to complete routes or schedule repairs.

With the updated software, operators will have substantially more time to diagnose and address eligible emissions system issues before the truck reaches its final speed limit.

The increased final speed limit of 25 mph also provides greater flexibility when moving the truck to a safe location or directly to a service facility.

The result is improved uptime, fewer unnecessary operational disruptions, and greater convenience for drivers and fleet managers.

EPA Compliance Remains Unchanged

While the software provides additional flexibility, it does not eliminate emissions requirements.

All PACCAR MX-powered vehicles must continue to comply with EPA emissions regulations. Any truck experiencing an emissions system fault will still require proper diagnosis and repair to remain compliant.

The updated calibration simply provides additional time to address qualifying issues before the vehicle enters its final inducement stage.

Schedule Your Software Update

If your Peterbilt is equipped with a PACCAR MX-11 or MX-13 engine and was built in 2018 or later, you may be eligible for this software update through your local Peterbilt dealer.

Our factory-trained technicians can verify your truck's eligibility, install the latest software, and ensure your vehicle continues operating at peak performance while remaining emissions compliant.

Contact your nearest The Pete Store location today to schedule your software update or learn more about your truck's eligibility.