Hey!!!
I have 3 codes on my '98 accord, 2.3 V-tech. Here are the codes, if anyone can give me some advise what should I do.
P0420 Catalyst Efficiency Below Threshold Bank 1
P0325 Knock Sensor 1 Circuit Malfunction
P0505 Idle Control System Malfunction
Thanks for any help !!!

 

find out if your knock sensor is attached or broken off.

P0505 could be a a iacv that is disconnected, not working or dirty, so cleaning that would be a start, replace it if it still downt work.

catalyst below efficiency can mean needing a new catalyst or a new o2 sensor, or making a stand off out of spark defoulers (two of them drilled out and screwed onto secondary o2 sensor then screwed into exhaust).

 

well, i replaced the knock sensor. after i instelled it, i noticed that the plastic part was broken off. i took it out, fixed it put it back in. The iac, same thing. took it off, cleaned it (was pritty dirty) put it back on. I reset the comp. and this codes came on. The o2 sensor is brand new, so i'm thinking about the converter itself.
do you know how can i test the iac if it's working or not?
thanks a lot for ur info!!!

 

when you say you fixed a broken knock sensor...how exactly do you do that?

i dont have the exact manual for your car, but look around and download a helm manual they will ahve some trouble shooting stuff for the IACV, and i would look up the spark plug defouler trick for the secondary o2 sensor...

 

THE KNOCK SENSOR HAS ONLY A WIRE INSIDE. SO THAT WIRE WAS BROKEN OFF. I JUST SOLDER THE WIRE BACK, AND PUT THE PLASTIC CAP ON.