Peterbilt truck repair & roadside — mobile diesel mechanics
Peterbilt is PACCAR's premium Class 8 brand (models 579, 567, 389). Most are spec'd with the PACCAR MX-13 — the same long block as the Kenworth and DAF MX — or the Cummins X15. Like its siblings, the bulk of roadside calls are aftertreatment and electrical, not bottom-end mechanical.
Send one request — nearby diesel techs see your truck and fault info before they quote you.
Common Peterbilt problems & roadside issues
- PACCAR MX aftertreatment faults (DPF differential pressure, DEF dosing, SCR efficiency)
- DEF quality and NOx-sensor faults that drive SCR inducement derates
- EGR cooler and EGR valve faults on the MX-13
- Chassis electrical / J1939 datalink faults from connector corrosion
- Air-system and cooling faults that trigger engine-protection derates
Peterbilt engines
Pick your engine for engine-specific common faults and fault-code help.
The PACCAR MX-13 is a 12.9L inline-six shared across Peterbilt, Kenworth, and DAF. It's a popular line-haul choice known for light weight and fuel economy. Aftertreatment and EGR faults dominate its roadside diagnostics.
Cummins X15 15.0LThe Cummins X15 is the heavy-duty option in Peterbilt 579/567/389 trucks for fleets that want a 15L and a wide independent service network. Its aftertreatment and EGR systems account for most roadside faults.
Throwing a fault code?
Look up what a heavy-duty SPN/FMI code means — DPF, DEF/SCR, engine protection, oil pressure, and more — then get a mechanic dispatched. Open the fault-code lookup ›
FAQ
Yes — most Peterbilt roadside calls are aftertreatment (DPF/DEF/SCR), electrical, air-system, or EGR faults that a mobile diesel tech can diagnose and often resolve on-site with a scan tool. Severe internal failures or a fully plugged DPF need a shop.
The most common Peterbilt roadside issues are: PACCAR MX aftertreatment faults (DPF differential pressure, DEF dosing, SCR efficiency); DEF quality and NOx-sensor faults that drive SCR inducement derates; EGR cooler and EGR valve faults on the MX-13.
Peterbilt trucks are commonly spec'd with PACCAR MX-13, Cummins X15. Pick your engine below for engine-specific fault-code help.
Find a Peterbilt mechanic near you
General repair guidance for heavy-duty diesel trucks. Not a substitute for a scan-tool diagnosis on your specific Peterbilt.