Will a purge valve set a code of P0455?

Question

When vacuum is applied to gas tank side of valve it starts to slowly leak

Answer 1

P0455 Evaporative emission system leak detected (large leak)

Yes it can. . if the purge does not close properly while monitoring the FTP (fuel tank pressure) sensor P0455 can set , That or a P0442 which is a small leak detected. What it is supposed to do is set a P0441 which is incorrect flow detected ,where the FTP detected a vacuum In the fuel tank at idle. Usually you can hear a faulty purge valve, if it slightly stick open, there would be a gulping noise created  from the intake vacuum . when it is suppose to be off and closed. You would think the FTP would detected vacuum, but that not always the case.