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Heavy-duty truck help center
Practical, no-nonsense guidance for drivers and owner-operators when something goes wrong on the road. These guides are written and maintained by the team behind the RoadService.app provider directory. Know the symptoms, understand common next steps, and use the directory to find and call a provider when you need professional help. Availability varies by provider and location.
Broken down right now?
Breakdown & repair guides
Every guide is free, indexable, and written for roadside reality.
Emergency DEF & DPF Repair for Trucks
DEF warnings, DPF alerts, or reduced power? Record the exact messages, confirm your engine details, and ask a qualified provider what can be diagnosed at your location.
Mobile Reefer (Refrigeration) RepairA reefer alarm or changing temperature needs a clear service call. Have the unit details, alarm messages, temperature readings, and load contact ready before calling a refrigeration provider.
DOT Inspection & Roadside Compliance RepairFailed a roadside DOT inspection or need to clear a defect to get back in service? Here's the fast path.
Mobile Trailer Repair & ServiceTrailer lights, air leaks, brakes, or landing gear causing trouble? Describe the trailer and its location, then confirm whether a provider can assess it safely on site.
Air Brake Repair for Semi TrucksAir leaks, low pressure, or dragging brakes are safety-critical. Don't roll on compromised air brakes.
Truck Broke Down on the Highway? Driver Safety StepsA breakdown in a live lane is one of the most dangerous things a driver faces. Here's exactly what to do — in order — to stay safe and get rolling.
DEF/DPF Derate & Limp Mode Explained — How to Avoid a Tow"Limp mode" — the engine derate — is your truck protecting itself. Understand what triggers it, what the speed limits mean, and how to keep a 5 MPH derate from turning into an expensive tow.
Diagnose & look up your fault
Got a code or a make-specific problem? Start with these tools, then jump back to a guide or find a provider near you.
Fault code lookup (SPN / FMI)
Plain-English meanings, severity, likely causes, and what to check first — Cummins, Detroit, PACCAR, Volvo, and Mack.
Truck repair by make & engineCommon problems and fault-code help by make — Freightliner, Peterbilt, Kenworth, Volvo, International, Mack, and more.
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Enter your location and the service you need to see listed providers sorted by distance, then contact one directly. RoadService.app does not assign providers or coordinate repair work.
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