Sharing in case others get this issue.
Couple months ago I got the P0456 - Evaporative Emission System Leak Detected- Very Small. Reset the code but it returned a couple days later.
It was recommended that I change the gas cap, which I did ($15 from local dealer).
Happy to say that the issue has not returned.

 

Had the same issue, but I only replaced the gas cap gasket which had a numerous visible cracks. After replacing, code was gone as well, and for a bit less at about $6.

 

Dang now why didn't I think of that!!

 

Bumping an old thread.
The new gas cap worked for a while but the P0456 code returned after a couple of months.
As others have done I ended up replacing vent hose 99711002973. It has been over a year since I replaced the hose and no codes have returned.

 

Wow, not an inexpensive fix. Did you see were the other one failed?

Ed

 

Ya cost me about $180 I believe. I still have the original and my mechanic says it is fine
I "believe" that maybe the valve doesn't always close all the way or something. Never did verify it myself. Could be coincidence but its been long enough now that i think it was the culprit.
I remembered about it today as I am going in this week to get my yearly state inspection (lean tune week) and can't pass with that dumb code.

 

Yep, same thing happened to me, I tested it and found it to be bad.. https://rennlist.com/forums/997-turb...l#post14844762