Volvo All Engines (2010 Emissions) Fault Code: SPN 5392 FMI 31 PID: PSID 121 Aftertreatment DEF Dosing Unit Loss of Prime

The aftertreatment control module (ACM) monitors the pressure build up in the diesel exhaust fluid (DEF) dosing system. This diagnostic function checks the time it takes for the DEF dosing pressure to reach more than 650 kPa (94 psi). If the pressure is not reached in 20 minute(s) this DTC will be set.

Conditions for diagnostic trouble code (DTC):
1) Aftertreatment DEF Dosing Pressure Lower than expected

Observable symptoms
1) No aftertreatment diesel exhaust fluid (DEF) dosage
2) Engine de-rated

Probable cause
1) Empty tank
2) Frozen aftertreatment diesel exhaust fluid (DEF)
3) DEF Supply from Aftertreatment DEF Tank disconnected
4) Aftertreatment DEF Line(s) Leakage
5) Aftertreatment DEF dosing valve Leakage
6) Aftertreatment Diesel Exhaust Fluid (DEF) Pump Leakage
7) Damaged sending unit inside the aftertreatment DEF tank
8) Damaged or clogged filter
9) Aftertreatment DEF Dosing Pressure Sensor, Incorrect value
10) Aftertreatment Diesel Exhaust Fluid (DEF) Return Valve
11) Blocked DEF tank ventilation hose
12) Air in the system
13) Crystallization inside the DEF pump
14) Low level in Aftertreatment diesel exhaust fluid (DEF) tank
15) Contamination or debris inside DEF tank