Volvo All Engines (2010 Emissions) Fault Code: SPN 3491 FMI 3 PID: Aftertreatment DPF Atomization Air Actuator

The atomization air valve is part of the atomization module and the combustion air valve is located on the engine. Both are controlled by the same DPF ECU output. The valves are normally closed and are opened when voltage is supplied by the DPF ECU. When opened, compressed air supplied from the air tank through the priority valve is supplied through the atomization air valve to the atomization nozzle while charged air from the intake manifold is supplied through the combustion air valve to the DPF Unit combustion chamber.

Conditions for diagnostic trouble code (DTC):
1) The voltage at pin A137:29 is above normal value

Probable cause
1) Wiring harness between Aftertreatment Diesel Particulate FIlter (DPF) Combustion Air Valve and Aftertreatment Control Module (ACM)
2) Aftertreatment Diesel Particulate FIlter (DPF) Combustion Air Valve
3) Aftertreatment Diesel Particulate Filter (DPF) Atomization Module
4) DPF Control Unit
5) Basic checks