Volvo All Engines (2010 Emissions) Fault Code: SPN 3251 FMI 0 PID: 81 Aftertreatment DPF Differential Pressure

The function identifies and indicates malfunction of the aftertreatment diesel particulate filter (DPF) by analyzing the pressure drop over the aftertreatment DPF. This is done by making a check for deviation between sensor value and a model pressure drop. In some extreme cases the engine will derate.

Conditions for diagnostic trouble code (DTC):
1) High differential pressure across the filter (> 35 kPa (5 psi / 10.3 in-Hg))

Observable symptoms
1) Low Power
2) Medium to high derate

Probable cause
1) Excessive smoke from the engine
2) Aftertreatment diesel particulate filter (DPF) is loaded with soot
3) Aftertreatment diesel particulate filter (DPF) is loaded with ash
4) Incomplete regeneration, driver has not allowed regeneration to complete
5) Regeneration inhibited, driver has not allowed regeneration to take place
6) Charge air system leakage
7) EGR System Faulty
8) Aftertreatment DPF Differential Pressure Sensor