METHOD FOR DIAGNOSING STUCK OF EVAPORATED FUELPROCESSING SYSTEM USING NATURE NEGATIVE PRESSURE

摘要

Disclosed is a method for diagnosing a malfunction of an evaporated fuel processing device by using natural negative pressure. The method for diagnosing a malfunction of an evaporated fuel processing device by using natural negative pressure includes a step (a) of confirming whether conditions for generating the natural negative pressure in a fuel tank is satisfied; a step (b) of measuring operation time of a natural negative pressure switch while an engine is stopped and storing an external temperature; a step (d) of determining whether the operation time of the natural negative pressure switch exceeds a preset time while the engine is stopped; a step (e) of confirming whether the natural negative pressure switch is on or off; a step (f) of confirming whether maximum opening control of a purge valve starts; and a step (i) of determining whether a limit elapsed time according to a fuel level passes.