Volvo All Engines (2017 Emissions) Fault Code: P04DB00 PID: EMS Crankcase Ventilation System Disconnected

The Crankcase Pressure Sensor is used to detect crankcase pressure system failures. The sensor consists of a pressure sensitive diaphragm and amplifier. Crankcase pressure causes the sensor’s diaphragm to deflect and produce an electrical signal proportional to the pressure. The diaphragm deflection signal is amplified in the sensor.
The engine control module (ECM) will set a diagnostic trouble code (DTC) if the sensor signal is not within predetermined limits. The ECM can also disable the engine brake, derate or shut down the engine to avoid engine damage.
The sensor’s signal is monitored by the Engine Control Module (ECM).

Probable cause
1) Leakage in crankcase system hoses or connections
2) Low oil pressure causing drop in crankcase ventilation RPM
3) Crankcase ventilation, Separator