Hello forum,

I've had the evap system error P1456 for a few years now and figured that I'd tackle it this spring. Since everyone who has checked it has found no problems, I assumed it may be the charcoal canister or a rusty fuel neck, but it hasn't bothered me a lot, so I've just been turning off the light on my own and ignoring it. The problem has to be in the EVAP system somewhere though.

Oddly enough, this winter, I've noticed that often times when the temperature falls below freezing, the SES light will turn off. The P1456 code is the only code I've been seeing and clearing, so it's no other. I find this a bit odd, and was wondering if anyone knew what the cold weather might be affecting to cause this error to be cleared temporarily. It's not like the battery has been dead, or that I haven't driven it in a while. I drive this thing daily, and have had this occurrence before and after I got a new battery, so it's nothing with the ECU.

Any help is greatly appreciated.
Thanks!

Tiny crack in the canister closes due to temperature related contraction? I'd check your EVAP vent valve for leak and its seat for cracks, very common causes for this code.

I'm really hoping that's it. Would be very easy to fix...

The light is back on today, still freezing, but only difference is that it's not snowing.

I haven't seen anything else for this code on the forum and it can also wait until warmer weather.

Maybe the canister has water in it from a leak somewhere and freezes up. Is the little air filter on it or did it break off?

Something in the evap system is leaking and due to cold temperature probably freezing or something...

Then there's like 5+ pages worth of how to diagnose the problem
http://www.nicoclub.com/FSM/Maxima/2002/EC.pdf

I told Cotozic that if I figured this one out I would post it to save some headaches for future searchers.

The resolution was replacing the charcoal canister.

Long story short; I had checked all hoses for visible leaks and there were none. i figured it must be a failing purge valve on the canister. I replaced the purge valve, and the light was still on. I returned it and while I had the canister off, I decided to seal any kind of crack or joining point with silicone. This also failed.

The problem was within the canister itself.

Problem solved. = Replaced the charcoal canister.

I know it can be interesting when searching google for issues like this so I would also like to include;

My engine light would shut off if the temperature outside reached 28 degrees or below, which was the only time I could pass emissions. The day that it would hit 32+ the light would immediately reappear.

I hope this helps!

Glad you got it all sorted. Like I said before, it won't fault if it's below a certain temp. I'll happily accept a charcoal canister if someone wants to donate haha