If you own a diesel vehicle that requires the use of DEF (Diesel Emission Fluid), you may be frustrated with the programming that senses the emission system causing the vehicle to go into “Limp Mode” if any of the sensors go out of range. This has caused havoc within the transportation industry since 2007, causing vehicles to go from 65 mph to 15 mph until the problem in the system is resolved. This is problematic if your vehicle experiences the “Limp Mode” where no services are available.

While DEF will not be going away anytime soon, by 2027, EPA regulations require new trucks to avoid sudden, severe power loss if DEF runs out. Instead, a graduated “derate” schedule will provide warning time, preventing dangerous situations. DEF cannot be completely eliminated, because it is crucial for meeting NOx emission standards.

These rules affect new vehicles starting in 2027; existing vehicles do not require retrofitting.

Happy Motoring.