GENUINE HONDA PCV VALVE K-SERIES CIVIC EP3 INTEGRA DC5 K20A K20A2Genuine Honda PCV Valve. The PCV valve is a vital mechanical valve responsible for controlling positive crankcase ventilation. Sometimes these can stick or block up, either fully or partially. A faulty valve can cause idling or running issues and is also attributed to excessive smoking from the exhaust. If you suspect your PCV valve is faulty it should be replaced as soon as possible. If left the crankcase pressure can cause issues with piston rings