First of all, thanks very much to everyone on here who has responded to my questions and offered help. This site is a great resource.

JB, I followed your troubleshooting post in the DIY section for my 2000 Accord 4 cylinder with the P1457 code. Your entries are in quotations. Here's what I've done so far:

Note: I supplied voltage directly from the battery with a jumper each time and used a jumper to achieve ground, so the PCM has not been tested. The reason I did the tests this way, other than it was easier, was just to confirm that each valve was good.

Checks good.

This one stumped me. After checking several times, I'm certain that this valve is working in exactly the OPPOSITE way that it should from the above instructions. I can't think of any way that it would work in reverse. Valve holds vacuum at rest, but drops it when energized.

Checks good.

Well, that's where I'm at right now. Every time I reset the code with my AutoXray 6000, I get about 3 or 4 drive cycles before the CEL comes back on. Any further help would be greatly appreciated.

 

Sorry, I stayed far away from my computer during the holiday weekend...

The 2-way valve was confusing to me. Worse yet, I don't have that Helm book any more (sold it after I sold that car). The instructions for which hose to plug & which to check were confusing, and at the time I wasn't sure whether I had it right. I actually bypassed that and tested the vent-shut valve. THAT one was corroded & didn't even click, so I never had to go back & resolve what's what with the 2-way valve.

Here's a thread with user rjpjnk that has some more about the 2-way valve. He had P1456 so it's not exactly the same. Don't know whether any of this thread will help you?
https://www.hondaaccordforum.com/for...ad.php?t=27756

 

Jim, thanks for the reply. I guess I'll consider the two-way valve as "good" for now. I mean, my reasoning is that if it were broken, it wouldn't work at all. Since it appears to work, but in reverse of the instructions referenced above, I'll look elsewhere.

I looked at the link to the thread that you provided, but it seems that that thread was addressing the P1456 (tank side) code. I'm dealing with a P1457 (canister side) code.

I'm considering pulling the canister itself from under the car, plugging it up and pulling a vacuum on it to see if the canister itself is leaking.

FWIW, the car has never been in a road-salt environment and everything underneath looks pretty good.

 

I linked that thread because that 2-way valve is part of both systems, and rjpjnk had a tech-bulletin with some clarification of how to test the 2-way valve.

 

Thanks. Missed that part. The bulletin excerpt that rjpjnk linked to in that thread was greek to me. Didn't understand the charts. I'm now trying to search to see if my AuotXray 6000 scan tool will read fuel tank pressure. I'm at work & my scan tool is at home.

Some of these service bulletins that I've been able to access on here and elsewhere are confusing, partly because the bulletins assume you've got access to the Honda diagnostics equipment.