Abstract: A diagnostic system and method for a crankcase ventilation system of an engine having a boost system utilize a pressure sensor configured to measure a pressure in a make-up air (MUA) hose, a flow-limiting valve (i) fixedly attached to the induction system at a point 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, and a controller configured to, in response to detecting the non-boost operating condition of the engine, obtain an initial pressure from the pressure sensor and then command the flow-limiting valve to close for a diagnostic period, during which monitor the pressure is monitored to determine a pressure drop from the initial pressure, and when the pressure drop fails to exceed a threshold during the diagnostic period, detect a malfunction indicative of a leaking or disconnected MUA hose.

Abstract: A diagnostic system and method for a crankcase ventilation system of an engine having a boost system utilize a pressure sensor configured to measure a pressure in a make-up air (MUA) hose, a flow-limiting valve (i) fixedly attached to the induction system at a point 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, and a controller configured to, in response to detecting the non-boost operating condition of the engine, obtain an initial pressure from the pressure sensor and then command the flow-limiting valve to close for a diagnostic period, during which monitor the pressure is monitored to determine a pressure drop from the initial pressure, and when the pressure drop fails to exceed a threshold during the diagnostic period, detect a malfunction indicative of a leaking or disconnected MUA hose.