Volvo All Engines (2010 Emissions) Fault Code: SPN 3936 FMI 1 PID: PSID 28 Aftertreatment DPF System

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) DPF Differential pressure too low

Observable symptoms
1) None

Probable cause
1) DPF Sensor lines connected incorrectly
2) Differential pressure sensor lines plugged or damaged
3) Aftertreatment DPF Differential Pressure Sensor
4) Aftertreatment Diesel Particulate Filter (DPF)
5) Exhaust leakage prior to the aftertreatment diesel particulate filter (DPF) unit