Thread: 0442 code?

Ive had this problem for a couple of years. Replaced purge valve, another part behind the left rear wheel inner plastic fender, had the dealership do a smoke test which detected no leaks but they replaced fuel pressure sensor. Light stayed off for about 2 weeks, then came back with same evap code. I have not replaced the fuel cap recently(current one is a few years old) I concluded from another post on this subject that a smoke test will NOT necessarily detect a small leak at the fuel cap. Is this correct? What other components in the EVAP system are there? Thanks