Volvo All Engines (2017 Emissions) Fault Code: P203B00 PID: EMS Aftertreatment Reagent Level Warning

Circuit description
The reductant level sensor is integrated into the reductant quality module and monitors the level of DEF in the DEF tank.

Conditions for diagnostic trouble code (DTC)
The deviation between the highest and lowest levels in the DEF tank was monitored during a self-test of the following component(s): DEF quality, level and temperature sensor

Probable cause
1) Aftertreatment diesel exhaust fluid (DEF) tank, Level Sensor
2) Clogged DEF system
3) Aftertreatment diesel exhaust fluid (DEF) tank, Incorrect mounting
4) Aftertreatment DEF dosing valve