Volvo All Engines (2013 Emissions) Fault Code: P20E892 PID: ACM Reductant Pressure Too Low

Circuit description
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)
Aftertreatment DEF Dosing Pressure Lower than expected

Observable symptoms
No aftertreatment diesel exhaust fluid (DEF) dosage
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) Blocked DEF tank ventilation hose
11) Air in the system
12) Crystallization inside the DEF pump
13) Low level in Aftertreatment diesel exhaust fluid (DEF) tank