New to the forum, just purchased a two owner 99 Accord 2.3VTEC automatic with 197k miles of southeastern driving. Cleaned up real nice and has a lot of recent maintenance work done - New timing belt, water pump, tires, dist cap, wires, air filter, etc. Well anyways I bought it knowing there was a CEL on thinking it would be an easy fix. After digging into it a little bit it seems I've come to a dead end.

#1 - P0401 - EGR flow insufficient. This one seems pretty straight forward. I cleaned out the EGR and tried to clean most of the port leading to the upper manifold without taking it off. The code seems to come and go, looks like I might need to pull off the plenum and give it a good scrub.

#2 - P1457. After doing tons and tons of research, I realized how daunting this can be. I had been using JimBlake's Diagnostic thread until I've come to a dead end (https://www.hondaaccordforum.com/for...-1999-a-27179/)

First off I ground Pin4 on the PCM. Checked EVAP Purge Control Valve, held vacuum key off, did not hold vacuum key on. Next I moved to the 2-way valve under the car. I inspected all the hoses around the system and did not see any that were visually cracked. Checked 2-way valve by removing both side hoses, attaching mityvac to lower one, holds vacuum fine with key off. Key on and it still holds vacuum. So thinking this may be my issue I went ahead and ordered a new solenoid, installed it and reset the battery. P1457 came back within 2 days. I get underneath and realize I forgot to put a new O-ring back in, so it was leaking the whole time. Great, replaced the o-ring, double checked it held vacuum no problem. I went ahead and ground Pin4 on the PCM to make sure the new valve operated properly and it still holds vacuum key off or key on. So I double check the EVAP Purge Control Valve and it doesn't seem to be working either. Hmmm. I fiddle around with the paperclip in Pin4 to ground at the battery to body bolt and finally get the Purge Control Valve working properly for my test. Get underneath expecting for the 2-way valve to work and nope, still holds vacuum key on.

So either A) I'm not doing the diagnostic test correctly or perhaps it doesn't activate at Pin4 to ground, or B) The brand new Dorman part I worked doesn't work with crap.

I'm partially considering going ahead and ordering all new solenoids and canister and just replacing all the damn things at once, but I also don't want to spend a bunch of money on this car as I bought it for a beater and don't want to put in money I don't need.

Can someone point me in the right direction?

 

Forgot to mention this is an EX model

 

Dreaded 1457? I thought everybody gets that one.
I just took mine to the mechanic and he fixed it for $160 and no messing around with the ECU.

 

I wrote a lot of stuff about the "proper" diagnosis procedure. Don't let it all scare you away.

It seems that the vent-shut valve is a pretty common reason for that code, so you might want to go straight there. That vent-shut valve is located on the outboard end of the EVAP canister (under the car, sorta below the left-rear seat, just inboard from the rocker panel).

Unplug the wire from that valve, run some wires directly from the battery. Or from any 12v battery you might have in the garage. In my case, the valve was corroded and it didn't even make any clicking sound when I applied power. If that's the case, replace it.

The only time you need to go through the ENTIRE procedure is if you never find something that fails the testing. I presume Honda wrote the procedure so the first things you test are the ones that Honda thinks are more likely to fail.

 

I actually just ordered the vapor canister purge valve last night, after reading that it seems to be one of the most common causes of failure leading to p1457, particularly for the NE cars and their harsh winters.

 

Did you check that solenoid valve vs. the vent-shut valve? Hear it click or not?

I'm always leery of just buying parts without testing, especially when it's real likely that a failed valve will not even click when 12v is applied. That's a pretty easy test.

Also remember that P1457 really means that the canister system isn't airtight like it's supposed to be. Dried & cracked vacuum hoses?

 

If you are in the NE - Salt on the bolts that hold the valve to the canister....makes it reall fun to remove those bolts.

 

Can't p1457 also mean a failed solenoid valve? I've gone over all the vaccum hoses underneath the car and do not see anything.

 

P1457 can be due to different causes such as an EVAP Bypass Solenoid Valve failure; however, as JimBlake mentioned was to check whether you can hear the valves click.

Attached is Honda TSB 03-001 regarding P1457 and the EVAP Bypass Solenoid Valve. Even in this bulletin, it mentions to:

Listen for a click and feel for a light tap from the solenoid valve as you activate it.
• If you can hear the solenoid valve click or feel it tap when activated, disregard this service bulletin, and look for other possible causes.

 

I must've missed where you said you already checked for bad vacuum hoses.

Anyway, P1457 can be caused by a number of things including any of several solenoid valves. You check out each possibilty & if you rule it out you go on to the next.