Have had P0456 going on regularly for a few years now. 2009 G37 XS has ~175k miles. Have had the car since about 30k miles and it runs wonderfully.

Have replaced the canister vent valve, the fuel cap, and have tested the purge valve. Brought the car into firestone this last weekend and the performed a smoke test. According to the tech, the pressure held and no smoke was detected. Said they removed the back seat due to smelling gas (my son who drives the car has never smelled gas) but didn't find anything. The next recommended step was to remove the gas tank for visual inspection which would have cost $1000. I declined.

Last time inspection was due we timed the test so that the code had not yet popped up but the system showed "ready" which allowed the car to pass emissions. May try that again but I prefer to solve the issue so the light isn't on all the time. My son resets it about every other day.

The only thing I can think of is that there is a very small leak or perhaps the pressure sensor is bad. ANy ideas?

 

I had all kinds of EVAP codes near the beginning of the year and it ended up being a completely rotted hose sitting in the middle of other hoses that still looked new.

I posted something here: https://www.myg37.com/forums/g37-sed...tem-error.html

I put electrical tape around it for a while until I could get to AutoZone and buy a new piece of hose. Car ran bad until the tape was applied.

I also replaced the gas cap as that is almost as overlooked as the radiator cap.

 

I searched the forum before posting and saw your post! We're getting different codes - had never heard of your code before. Sounds like I need to do a visual inspection again. Firestone indicating that the system held pressure and smoke was not visible has me stumped. If I had a hose that looked like yours I think the smoke test would have been obvious.... unless it wasn't done properly. Sounds like you had a massive vacuum leak. Gate issues like this - need to CEL light to go off so I can pass emissions. Emissions must be passed in order to get a new license sticker.

Do not want to spend thousands to fix a light on a perfectly running car that's probably only worth $5k. May try a non-chain shop for another smoke test.