# Help with engine code 0456 - EVAP VERY SML LEAK



## sonixtwo (Nov 20, 2006)

I recently got a 2004 Sentra 1.8S. This last week or so, my Check Engine Light has been on. When I pull the code, I get 0456, which is EVAP VERY SML LEAK. 

I have been unable to identify what is causing this problem. 

The first thing I checked it the gas cap, and it is on securely. Inspecting the vacuum system visually as best I could, I saw nothing wrong either.

After I reset the code, while driving, if I release the accelerator just a little bit while cruising, the engine light lights up, but does not stay on. I can easily recreate this situation at any time. After restarting the car, the engine light stays solid until I reset it again.

Any information on what can cause this problem would be appreciated.

Thanks

-Mike


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## chelito92105 (Jan 19, 2007)

This post might be a little late but I recently also had an EVAP Circuit Open SES light on my car. The car had been hit in the rear and one of the hoses was pretty much going nowhere. It was originally just plugged up so I put a piece of plastic with some electrical tape and a zip tie and the SES light never came on since. My advice is check all the hoses in the rear under the gas filler and make sure none of them are cracked or anything. Also check your carbon box to make sure its sealed.


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## djkid (Apr 2, 2008)

there is small black box. right under the bumper behind the wheel on the right side. make sure both the hoses are in properly and securely. if the problem is still there you might have to change your Evap cannister which is that black box.


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## chelito92105 (Jan 19, 2007)

Yeah luckily the code stayed off until after the smog check but now it came back. This time with a "big leak." Im guessing Ill just replace the whole cannister now since it was probably impacted there. Any idea how much they would cost? I was thinking about a junkyard. Are all the boxes for the B15s the same? or are the SE-R ones different?


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## specv79 (Apr 4, 2008)

*me too evap small leak*

I had the same trouble with this 2002 spec-v I bought recently I've put 1000.00 in nissan parts and 7 hours labour at a rate of $75.00. I replaced the evap cannister, both 02 sensors, evap control senor, valve, catalytic convertor. I was flashing the same codes p0456.

Now I got a new problem hard starting. p0301 misfire cylinder 1. I'm going to switch the coil packs (1 with 4) and see what happens. I might have a bad coil pack my sentra has 200,000km with original ignition. Anyone know how long these units last? anyone had to replace coil packs afther 10),ooomiles?


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## djkid (Apr 2, 2008)

how much did the catalytic convertor cost you. im getting an SES on that code. thanks


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## revoltrise (May 3, 2008)

before you buy a new canister, take a look at the current one, and on the back side you'll see a valve with an electrical connector and two 3/8" rubber hoses going into it. pull that out of the canister and shake it around, if it rattles then you'll need to replace it. it is the evap vent control valve, and they go bad all the time. if it doesn't rattle make sure you lube the o-ring with silicone or wd-40 before you put it back into the canister, a leak there can also cause an evap leak.


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