VOLVOUU All Engines (2017 Emissions) Fault Code: P20B297 PID: ACM Reductant Heater Coolant Control Valve Control Performance/Stuck Open

VOLVOUU All Engines (2017 Emissions) Fault Code: P20B297 PID: ACM Reductant Heater Coolant Control Valve Control Performance/Stuck Open

Circuit description
This diagnostic trouble code (DTC) indicates malfunction in the aftertreatment diesel exhaust fluid (DEF) tank heater valve or related wiring. The function of the aftertreatment DEF tank heater valve is to allow engine coolant flow to the aftertreatment DEF tank heater element which keeps the DEF from freezing. Frozen DEF may result in no DEF dosing which causes limited vehicle operation.

Conditions for diagnostic trouble code (DTC)
Aftertreatment diesel exhaust fluid (DEF) temperature too low

Observable symptoms
Possible engine de-rate

Probable cause
1) DEF Tank Heating Valve installed backwards
2) Mechanical fault
3) Damaged or restricted actuator coolant lines
4) Aftertreatment diesel exhaust fluid (DEF) tank heater valve