Crankcase ventilation system and diagnostic method

A positive crankcase ventilation (PCV) system comprising:

• a crankcase including an interior chamber;
• an oil separator coupled to the crankcase;
• a PCV valve positioned in a PCV line coupled to the crankcase and an intake manifold downstream of a compressor;
• a ventilation line coupled to the oil separator and an intake conduit located upstream of the compressor;
• a pressure sensor positioned on a clean side of an oil separator and spaced away from an end of the ventilation line, the oil separator coupled to the crankcase;
• and
• a controller including instructions stored in non-transitory memory that when executed cause the controller to:
• while the PCV system is operated with a boosted engine condition where an intake manifold air pressure is above a threshold value and where a PCV valve in a PCV line coupled to a crankcase and an intake manifold downstream of a compressor meters gas flow to the crankcase, determine a PCV system breach based on a pressure determined using the pressure sensor.

A diagnostic method for a positive crankcase ventilation (PCV) system, comprising:

• operating the PCV system with a boosted engine condition where an intake manifold air pressure is above a threshold value and where a PCV valve in a PCV line coupled to a crankcase and an intake manifold downstream of a compressor meters gas flow to the crankcase;
• and
• while the PCV system is operated with the boosted engine condition, determining a PCV system breach based on a pressure measured using a pressure sensor arranged on a clean side of an oil separator coupled to the crankcase, where the sensor spaced away from an end of a ventilation line coupled to the oil separator and an intake conduit upstream of the compressor;
• and
• responsive to determining the PCV system breach, setting a diagnostic code indicating PCV system breach, notifying a vehicle operator of the PCV system breach, and/or implementing a mitigating action.