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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 roadside platform. Know the symptoms, understand common next steps, and use the directory or request form when you need professional help. Provider response and arrival are not guaranteed.
Broken down right now?
Breakdown & repair guides
Every guide is free, indexable, and written for roadside reality.
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.
Mobile Reefer (Refrigeration) RepairA reefer alarm with a loaded trailer is a clock you can't ignore. Find a unit tech fast.
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 down on the shoulder? Lights, brakes, airlines, and landing gear are usually a quick roadside fix.
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 submit a roadside request.
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.
One request. Availability-based matching.
Send your location and service need through RoadService.app. If an eligible approved shop is on duty and available, it may respond with an ETA and price for you to review before assignment.
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