SPN 3720 FMI 0 — DPF ash load very high — service required
Applies to: Detroit · Navistar · Paccar · Sae · Volvo · Typically 200-400k miles
DPF ash load very high — service required.
Your SPN/FMI rides along, so nearby mechanics see the fault before they quote you.
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.
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.