Emergency DEF & DPF Repair for Trucks
A clogged DPF or failed DEF system can derate your engine and strand you fast. Here's what's happening and how to get rolling.
Common symptoms
Check-engine + DEF lamps, forced regens, reduced power / 5 MPH derate, codes like SPN 3251/3719 or SPN 3361 FMI 7. Don't keep driving derated — it can escalate to a no-start.
What a mobile tech can do roadside
Force a parked regen, clear soot-loading faults, test the DEF doser/quality sensor, and get you to the next safe stop or shop. Severe DPF plugging needs a bake/clean at a shop.
Request help
Send your SPN/FMI codes and location through RoadService.app. If an eligible approved diesel tech responds, review the ETA and customer-facing all-in total, including any applicable RoadService job fee, before assignment.
FAQ
A forced regen and fault clearing can be done roadside; a fully plugged DPF needs a pneumatic/thermal bake at a shop. A mobile tech will tell you which you need.
The ECM derates to protect the aftertreatment system after repeated failed regens or a DEF fault. Address it quickly to avoid a no-start condition.
Find a mechanic near you
When you're ready for hands-on help, the RoadService.app directory connects you with vetted providers in your area.