Volvo All Engines (2017 Emissions) Fault Code: P204800 PID: ACM Aftertreatment Reagent Dosing Valve Short Circuit Low

When the aftertreatment selective catalytic reduction (SCR) system operates under normal conditions, the aftertreatment control module (ACM) monitors diesel exhaust fluid (DEF) dosing valve duty cycle and DEF pump control value. When the DEF dosing valve duty cycle increases above allowed threshold and the DEF pump control value decreases below expected threshold, the ACM stops DEF dosing and reports a fault. The fault might be indication of electrical failure or blockage in DEF dosing valve or DEF supply line from the DEF tank.

Conditions for diagnostic trouble code (DTC):
1) Short circuit to ground

Observable symptoms
1) No aftertreatment diesel exhaust fluid (DEF) dosage

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