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SPN 4782 — Soot density in filter

Safe to driveEnough to reach the yard

J1939 code SPN 4782. No factory wording for it in the reference — below is the standard meaning of FMI.

Common FMI values

SPN 4782 FMI 04782/0 · 4782.0data above normal range (most severe level)
SPN 4782 FMI 14782/1 · 4782.1data below normal range (most severe level)
SPN 4782 FMI 24782/2 · 4782.2data erratic or intermittent
SPN 4782 FMI 34782/3 · 4782.3voltage above normal or shorted high
SPN 4782 FMI 44782/4 · 4782.4voltage below normal or shorted to ground
SPN 4782 FMI 54782/5 · 4782.5current below normal or open circuit

Can I keep driving

Safe to drive. Below — how much time you have and what happens if you keep going.

What happens if you keep driving

Time you have: Enough to reach the yard

Urea dosing is interrupted and the ECU is counting. First the lamp, then a torque cut, then a forced crawl speed — the stages come in by engine hours, not all at once.

The truck will not die mid-highway, but the window shrinks with every running hour. Plan the repair now, not when the power is gone: an emulator or "deleting AdBlue" does not remove the problem, the codes keep stacking.

What to check on the spot

Fill the AdBlue tank. If it’s already full, the problem is dosing or reductant quality — you need a scanner.

Nearby: AdBlue / exhaust

Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.