Diagnostic system and method for detecting leaks and disconnects in a crankcase ventilation system

A diagnostic method for a crankcase ventilation system of an engine having a boost system, the diagnostic method comprising:

• detecting, by a controller of the engine, a non-boost operating condition of the engine;
• and
• in response to detecting the non-boost operating condition of the engine:
• obtaining, by the controller, an initial pressure from a pressure sensor configured to measure a pressure in a make-up air (MUA) hose or a crankcase of the crankcase ventilation system, the MUA hose connecting an induction system of the engine at a point upstream from an intake manifold of the engine to the crankcase,
• after obtaining the initial pressure, commanding, by the controller, a flow-limiting valve closed for a diagnostic period, the flow-limiting valve being (i) fixedly attached to the induction system upstream from the pressure sensor and proximate to an induction system end of the MUA hose and (ii) configured to limit flow through the MUA hose,
• during the diagnostic period, monitoring, by the controller, the pressure using the pressure sensor to determine a pressure drop from the initial pressure, and
• when the pressure drop fails to exceed a threshold during the diagnostic period, detecting, by the controller, a malfunction indicative of a leaking or disconnected MUA hose.