Hello:
Have a great running vehicle with 80 K. The CVT is Ok and accelerates fine.
However, just got a yellow code for EVAP issues code 0456. 
Repair shop said wait & see if it goes away.
Code reads very minor miniscule hole.
Did get a new gasoline fuel pump installed at 70 K. Could this be related?
What could it be & will temperature change with winter help? Car will be seven years old in a few months so not worth much ($$$)
Try replacing the gas cap. A bad one will throw that code and the seals do get old. Cheap repair, might take care of the code.
That code can be caused by a leaking gas cap.
If the light doesn’t go out, try applying a some petroleum jelly to the seal on the gas cap and reinstall the gas cap.
If the light goes out. replace the gas cap.
Tester
Not everyone will agree with me, and it usually doesn’t apply to this particular evap code, but make sure you don’t overfill your gas tank. Stop at the first click. If you have been overfilling, then just stopping at the first click from now on may stop your problem from returning.
BTW, it is most likely the gas cap, but you might not have a bad gas cap, it simply might have gotten a piece of debris on the seal one time or it just didn’t get fully tight one time. It happens.
You can’t overfill the gas tank on an OBDII vehicle.
There’s a component in the ORVR system called an Overfill Check Valve.
This valve also acts as a roll-over valve
Tester
You can and I have, and it was on a Nissan. Check valves do vibrate when going down the road and allow leakage if the tank is too full. Also if you fill on a hot day, the gas expands and creates pressure to help push that excess gas out.
You might have not screwed the gas cap on tightly enough one time and triggered this code. Clear the code, make sure the gasket doesn’t look worn or cracked, make sure it is tight, and then go on with life. If the code returns then change the gas cap. Clear the code. If it comes back then there are bigger issues. Gas caps are cheap so it is worth it to check before you go further into the problem.
Thanks.
For code P0456, Nissan, they replaced cannister valve on emis. system. Defined as minor leak.
Drove 2 days, 30 miles & light code P0455 major leak appears.
Maybe bad part or incorrect placement ???
Only change was new part. Takes a few miles for the system to cycle generate fault codes.
Thanks
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They fixed code P0456 minor leak.
Not gas cap, but emission canister valve.
Then day later code P0455 major leak…same part
Surprise. Maybe a mistake or bad part ???