Volvo All Engines (2010 Emissions) Fault Code: SPN 5485 FMI 11 PID: PSID 121 Aftertreatment 1 DEF Pump Orifice Flow

The aftertreatment control module (ACM) uses the aftertreatment diesel exhaust fluid (DEF) dosing pressure sensor value to adjust and maintain DEF pressure at the DEF dosing valve by controlling DEF pump speed. If the pressure decreases below expected value when the pump is in initial pressure build-up mode or if the pressure increases above expected value when pump is in idle speed mode, the ACM considers DEF pressure outside of normal operating range and indicates a malfunction in a DEF dosing pressure sensor.

Conditions for diagnostic trouble code (DTC):
1) DEF dosing pressure too high based on existing conditions

Observable symptoms
1) Low aftertreatment diesel exhaust fluid (DEF) solution consumption

Probable cause
1) Clogged internal bleed orifice
2) Blocked return line (damaged or frozen)
3) Crystallization in filter
4) Aftertreatment DEF Dosing Pressure Sensor