Volvo All Engines (2017 Emissions) Fault Code: P20A900 PID: ACM Reductant Injection Air Pressure Control Valve Circuit High

Volvo All Engines (2017 Emissions) Fault Code: P20A900 PID: ACM Reductant Injection Air Pressure Control Valve Circuit High

Conditions for diagnostic trouble code (DTC)
The voltage at pin A174.A:21 is above normal value

Diagnostic operating conditions
Ignition key in ON position

Observable symptoms
Uncontrolled air consumption

Probable cause
1) Short circuit to higher voltage
2) Connector
3) Wiring harness
4) Actuator
5) Aftertreatment Control Module (ACM)