P0455 code

[David in NC]

I got a second P0455 engine code. I got one a couple weeks ago and cleared it to see if it would come back. The advice here is to check the evap system; evap solenoid, canister, hoses, etc.
This may be a DAQ, but is the evap solenoid the same as the canister purge solenoid the same as the purge valve the same as the purge flow sensor?
Thanks.

 

[robertoa1a]

A bad gas cap can cause that. The Vacuum in the tank says there is a leak.