I posted this same problem 2 years ago right after the car passed Virginia Emissions.
The CEL came ON a week ago , two weeks after I took the car for Virginia emissions. I read the code and it came up [P1456] again, so I cleared it. It came back again, so I bought a new Gas cap and didn't reset the code to see if the Gas cap fixes the problem.

From what I have read, the Gas cap and the Evap Cannister are the most common problems, but doen't the Cannister problem throws P1457, not P1456?

Both times, the ECL came on after the Emission test, so could the Emission triggers this problem?

I know that 2 years ago when I posted about this, JimBlake was kind enough to give me some scenarios as to what the problem could be. Is P1456 code 95% related to a loose/damaged/or work gas cap ( gasket)?

The new gas cap looks black compared to the old gray one I had. Maybe this cap fixes the problem?

Thanks for any comments and thanks in advance for your time,
-Mott

2002 Accord EX-L 5 speed 187K miles

 

Search is your Friend

https://www.hondaaccordforum.com/for...ad.php?t=31104

 

Right, P1456 = tank
P1457 = canister

Either one means it's not airtight like it should be. Gas cap is mentioned in the owner's manual just because that's the only thing that Honda thinks a clueless driver can fix by himself.

Other things that can cause a fuel tank to leak...
Bad gasket where the fuel pump mounts into the top of the tank.
Bad gasket where the fuel gauge sender mounts.
Any of about a dozen rubber vacuum hoses up there & around the fuel filler neck.
I guess the tank itself might leak, but then you'd probably smell gasoline.

(The link that HondaDude provided is real good too)

 

Thanks [JimBlake] for your time. The link that HondaDude posted pertains to Accords 98 to 00, so it doesn't include 2002.

Could the Emission test had anything to do with the CEL since it came on right after the car passed emissions both times?

If the new gas cap doesn't fix the problem, do you know roughly how much it will cost to fix, assuming its the other stuff you listed.

The only thing I noticed is when I start the car the rpms go to 1200-1400 , but after the car warms they go down to 800 ( in neutral), so not sure if this is related. The throttle body has been cleaned and I put bg44K every 12k miles.

Thanks
-M

 

This powerpoint explains which evap systems problems trigger a P1456 code and which trigger a P1457:

http://www.asaillinois.org/09CAN/AsianEvap_1009CAN.pdf

 

1998 to 2002 are about the same for the EVAP system.

 

UPDATE:
This morning, on my way to work the CEL went off, so I assume the Gas Cap was the culprit.


just wanted to thank people who have responded. I'll keep an eye on this problem. Just glad I didn't have to take it for repairs.

regards,
-Mott