My car had 120k and been running fine. I replaced the cat about 6 months ago because of failing smoke chk, and never had cel-light before.
Lately, I got cels with code 1 (o2 sensor) and code 12 (EGR lift valve). I replaced O2 sensor with universal one, and cleaned EGR ports (by tps link from this forum) and EGR valve really well. The lift valve checked good, i.e. the car stalled when vacume applys to the hose. All voltages checked good at the EGR elec. connector and at the EGR solenoid. but both codes came back again.
Please helps! Thank you in advance.

 

you might of done this already, but did you reset the ecu, after you checked everything? pull radio backup fuse for a couple mins or remove the neg battery cable for a few...

 

yes, I did pull out the backup fuse a few times already after every test drive.
thanks Mike for your response.

 

just cleaned my egr 2 weeks ago. after i cleared the code, it came back on 30 miles later. i didnt have time to mess with it till a week later. due to the fact im kinda lazy, i just cleared the code again before i pulled anything apart again. my gas mileage had been so much better i suspected maybe it was just being overly sensitive ~shrug~. CEL never came back and ive put 400 miles on the car since. i guess maybe it takes a little while for the ECU to register after its been fixed.

 

do you have a friend with the same year accord? you guys can swap egr valves and see if the problem goes away...

when you said you cleaned out the ports on the egr,,, you cleaned the little holes too on the intake manifold correct? not just the metal plate that guides the gas through?

it seems like you have a manual and done the routine checks... but how about the electrical part? voltage? lift sensor?

 

unfortunately, my friend's accord is a 96 (obd2) and has different egr valve, so I cant swap and chk. I did swap the egr control solenoid (these are the same) and it made no different, thus, I assumed my control valve still good. I also did apply vaccume to the valve when engine is idle. The engine is killed right away. So I think the egr lift valve is good. and follows Haynes manual, all electrical voltage are chk and within normal range!!!!
Btw, I did take the entire fuel rail out and cleaned everything including all little holes. It makes the car runs better but would not clear the cels. It just came right back... It is reallllllyy frustration!
Is the lift sensor same as the lift valve that sitting next to the fuel rail? if not, please advice me what to look for and chk. thanks.

 

the lift sensors the one right on top of the egr valve itself.. egr control box is the thing under the plastic cover near the abs is equipped

 

by Haynes manual, I did chk the volt for the lift valve. It is within volt spec range.

 

This is weird!!! While I was driving to work yesterday, the cels cleared by itself. i have not done any fix to it. The cel is still off, but I will monitor it closely for the next few days. Thanks everyone.