Disclosed herein is a system and method for controlling evaporative emissions in an internal combustion engine. A control valve assembly having a valve housing having an inlet portion, a first outlet portion and a second outlet portion, and a vapor chamber is provided. The vapor chamber is situated within the housing and is in communication with the inlet portion, first outlet portion and second outlet portion. The assembly is configured to receive fuel vapors from a fuel vapor source, through the inlet portion into the valve chamber. The assembly is further configured to selectively actuate a piston member situated at least partially inside the valve chamber for communicating the fuel vapors in the vapor chamber to either: (i) at least one of the atmosphere and an engine air inlet system via the second outlet portion when the engine is operating or otherwise engaged to be operated, or (ii) to a crankcase of the engine via the first outlet portion when the engine is not operating.