Volvo All Engines (2013 Emissions) Fault Code: P20B400 PID: ACM Reductant Heater Coolant Control Valve Circuit High

Volvo All Engines (2013 Emissions) Fault Code: P20B400 PID: ACM Reductant Heater Coolant Control Valve Circuit High

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)
Short circuit to battery voltage

Probable cause
1) Connector
2) Wiring harness
3) Aftertreatment diesel exhaust fluid (DEF) tank heater valve
4) Dosage electronic control unit (ECU), pump unit