How Much Does DPF / DEF Repair Cost on a Semi Truck?
DPF cleaning, DEF sensor replacement, and SCR system repair are among the most frequent heavy-duty repair bills. Here's a realistic breakdown of what to expect — roadside and at a shop.
If an eligible provider responds, RoadService.app shows the customer-facing all-in total — including the RoadService job fee when applicable — before you accept.
Typical cost ranges
Ranges reflect 2026 US market rates. Actual costs vary by region, time of day, parts availability, and make/model.
| Repair / service | Low estimate | High estimate |
|---|---|---|
| Roadside forced regen + fault clear Mobile tech forces a parked regen, clears soot-loading faults. Doesn't include underlying cause diagnosis. | $200 | $500 |
| DEF quality / level sensor replacement Parts cost varies significantly by make (Cummins vs. Detroit vs. PACCAR). Labor is 1–2 hours. | $300 | $900 |
| DEF doser / injector replacement Dosers fail from DEF contamination or heat; genuine OEM parts cost more. | $400 | $1,200 |
| NOx sensor replacement Upstream or downstream NOx; both may need replacement if one fails. | $300 | $700 |
| DPF bake/pneumatic clean (at shop) Thermal or pneumatic cleaning; extends DPF life vs. replacement. | $400 | $800 |
| DPF replacement (aftermarket) Aftermarket price; OEM can run $3,000–$7,000+ depending on make. | $1,500 | $4,000 |
| Full aftertreatment system rebuild DOC + DPF + SCR replacement with OEM parts; rare but happens on high-mileage trucks. | $5,000 | $15,000+ |
What affects the price?
A first-stage derate caught by a mobile tech — forced regen plus sensor swap — can cost $400–$800. The same truck ignored until a no-start will need a tow plus shop time on top of that.
Contaminated or diluted DEF (water, wrong fluid) destroys dosers and sensors fast. Quality DEF from name-brand sources prevents expensive repairs.
Aftermarket DEF sensors and dosers cost 30–60% less than OEM. Most run fine; some OEM-calibrated systems reject aftermarket parts.
Cummins ISX, Detroit DD15, and PACCAR MX-13 are the most common and have the most parts availability. Specialty makes and older trucks may require longer parts lead times.
FAQ — DPF DEF repair cost semi truck
A roadside forced regen costs $200–$500. A full shop DPF bake or pneumatic clean runs $400–$800. DPF replacement (aftermarket) runs $1,500–$4,000.
Expect $300–$900 all-in for a mobile roadside replacement, including parts and labor. DEF quality/level sensors are the most common failure.
Many can — forced regens, sensor replacements, and DEF system faults are routine mobile repairs. A fully plugged DPF or a failed catalyst needs a shop.
Act at the first warning lamp — a $300 roadside sensor fix beats a $3,000 DPF replacement. Use quality DEF (ISO 22241), avoid extended idles, and don't drive through derates.
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Cost estimates reflect 2026 US market averages and do not constitute a quote. Actual prices depend on your location, vehicle make/model, fault severity, time of day, and provider rates. Always get an itemized quote before work starts.