SPN 3720 FMI 0 — DPF ash load very high — service required
What it means: DPF ash load very high — service required.
How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.
Check first: Remove DPF for ash cleaning (pneumatic/thermal)
Don't risk it — look up listed providers near you and give them this SPN/FMI when you call.
Listed providers nearest Macon, GA
Closest first. Tell them SPN 3720 FMI 0 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Macon, GA · (478) 538-3245
- 0.0 mi away — based in Macon, GA · (478) 216-8330
- 0.0 mi away — based in Macon, GA · (706) 536-3376
Applies to: Detroit · Navistar · Paccar · Sae · Volvo · Typically 200-400k miles
What SPN 3720 FMI 0 means
DPF ash load very high — service required.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Normal ash from mileage (non-combustible oil additives)
- Running a regen — ash does NOT burn off
- Normal ash accumulation from mileage
- Service cleaning required
- Running another regen (won't remove ash)
- Normal mileage ash
- Normal mileage ash accumulation
First moves (roadside)
- Remove DPF for ash cleaning (pneumatic/thermal)
- Remove DPF for ash cleaning
- Service cleaning
- Service DPF cleaning
FAQ
DPF ash load very high — service required.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Normal ash from mileage (non-combustible oil additives). Other possibilities include Running a regen — ash does NOT burn off; Normal ash accumulation from mileage; Service cleaning required; Running another regen (won't remove ash); Normal mileage ash; Normal mileage ash accumulation.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside SPN 3720 FMI 0, or share the same subsystem.
- SCR Operator Inducement — Severe Derate Active (SPN 5246 FMI 0)
- Aftertreatment 1 Diesel Particulate Filter Differential Pressure - Data Valid But Above Normal Operating Range, Most Severe Level (DPF severely restricted / plugged) (SPN 3251 FMI 0)
- Aftertreatment 1 Diesel Exhaust Fluid Quality - Data Valid But Below Normal Operating Range, Most Severe Level (DEF quality/concentration incorrect) (SPN 4364 FMI 1)
- DPF Differential Pressure — Data Erratic (SPN 3251 FMI 2)
- DEF Dosing Unit — Not Responding Properly (SPN 3361 FMI 7)
- SCR Conversion Efficiency — Below Threshold (SPN 4364 FMI 18)
- DEF Quality — Out of Spec (SPN 4094 FMI 31)
- EGR Temperature — Too High (SPN 412 FMI 0)
Same symptom: Regen problems
Other codes that block a regen or come back as soot load climbing.
- DPF Soot Accumulation Restriction (P2460) · Aftertreatment & Emissions
- DPF inlet temp sensor — voltage high (SPN 3241 FMI 3) · Aftertreatment & Emissions
- DPF outlet temp erratic (SPN 3242 FMI 2) · Aftertreatment & Emissions
- DPF outlet temp sensor — voltage high (SPN 3246 FMI 3) · Aftertreatment & Emissions
- DPF differential pressure — voltage high (SPN 3251 FMI 3) · Aftertreatment & Emissions
- DPF differential pressure — voltage low (SPN 3251 FMI 4) · Aftertreatment & Emissions
Find a mechanic or related guides
General diagnostic guidance for heavy-duty diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack). Not a substitute for a scan-tool diagnosis on your specific truck.