Hello, I have a 2008 Accord 4 cylinder that has the P0455 and P0456. I made a smoke machine to look for the EVAP leak. I replaced the gas cap a few months ago when I first got the code because I didn't have the smoke machine to check for the leak. I didn't get the OEM Honda gas cap though. Well today I hooked up the smoke machine and I found a couple places where I was getting a leak. One is the gas cap! There was smoke pouring out around the gas cap! I ordered the OEM Honda cap. The other place I was getting smoke is the little device next to the EVAP canister behind the left rear tire. I looked up the part and it is the Fuel Drain Box. There is a big hose and I little hose connected to it. Smoke was pouring out the big hose. When I opened the plastic box that the hose was connected to there was nothing inside the box. I looked up the part and in the exploded view the box looks like there is a cap inside where the hose connects, see pic #11. I wonder if there was something inside and it rotted away?



Is anyone familiar with the EVAP system on these Accords?


TIA.

 

Those codes may just be related to the gas cap not sealing. After every fill-up, turn the gas cap at least 3 clicks. Even with the new OEM gas cap, get in the practice of turning the gas cap at least 3 clicks.

The large hose that connects to the drain box is the evap drain hose. Inside the box, an option is to install a fuel drain spring due to EVAP canister vent shut valve close malfunction and spider webs. See this attached service bulletin.

TSB A08-87

 

Thank you very much for the reply and the link. I ordered a new drain box. Should there be smoke coming out of that large drain hose when I ran the smoke test? I thought if there is smoke coming out then the system can't pressurize.

 

Since the canister vent shut valve is normally open, if you did a smoke test without using a scan tool to command the vent shut valve to close, smoke will come out that end. Was smoking coming out, with the vent shut valve closed?

 

Oh, I see, I didn't realize that the drain valve was normally closed. I have a Ancel AD510 scan tool that says it can perform EVAP tests but when I try to run it on the Accord it says it is not compatible and will not run the EVAP test, so I don't think there is a way to close the valve. I did see smoke coming out the gas cap when I ran the smoke test so I am assuming there is an issue with the cap not sealing. I am hoping that is my problem, I didn't see smoke anywhere else other than the large drain hose, but that would make sense it the valve was open,

Thank you very much for your help.

 

The brute force way to close the vent-shut valve is to unplug it from the wiring harness. Energize it with some wires directly to the battery, or any source of 12v for that matter.