Evap canister Leak?

[Promise Land]

I've had this issue for the last month. My SES light comes on at about 3/4 tank (~120miles on the tank) but will go off when I fill up. I've changed gas caps already, but still happens the same time frame. I pulled the DTC codes and they are P0455 (Evap System - Gross Leak) and P0442 (Evap System - Small Leak). Anyone ever heard of this before? I thought it was just me not tightening the cap correctly, so I've changed caps too.

[led hed]

i had this experience on my spec-v before. i continued driving it. the evap cannister was no good, but still passed emmisions. aparently when one 'tops up' the tank when refuelling, fuel can leak into the cannister damaging it. so now i don't 'top up' anymore in my versa, i just round to the nearest 10 cents.

[08versailles]

Had no SES lights yet in the V. I verified it still works.

01 sentra threw Evap codes all the time.
Did not indicate gross or small size.
Would clear itself and re-trigger without pattern.
Would also trigger SES for running rich, but would clear itself with short trips and higher rpms Try that!
Never did anything about SES light until needed new MAF sensor at 153000km.
IMO do nothing until SES blinks, rather than steady glow.

[Promise Land]

I'm taking it in Monday to be serviced. I know what the problem is. I'll just let the dealership fix it since it's an emissions and fuel system problem.

[Promise Land]

Just a follow-up note on this.

I took it to the dealer, but they came back with No Problem Found and made sure the fuel cap was tightened correctly.
The real problem on the situation, based on some conversations I had with people, is that the canister check valve was working intermittently. I say it is that because the evap system checks the pressure between 80% - 20% fuel in the tank. The light would turn off when I filled up fully and come back on when I got about 120 miles on the tank, ~3/4 tank (or ~80% fuel). The "turns on at ~120miles" was the tip off that it was the valve. I replaced the valve last night since the dealership couldn't produce a fault and cover it under warranty. The light would come and go with each fill up and happened for about a month before I figured out what was happening.

Anyway, if you experience this situation, there's your help on it. It may be the fuel cap if it happens once or twice. If it's repetitive, it may be the valve instead.

[NODES]

Next time the SES light comes on take right to Nissan....I hate when they give you the "No Problems Found" yeah because we make this crap up and waste our valuable time to visit the dealerships...shesh