Si_chRis

So my 2000 Civic SI is throwing the P0420 code for catalyst below efficiency threshold. I'm about to order a new OE replacement cat converter and was wondering if I am better off replacing the secondary 02 sensor also or re using my old one?

Anon51

if you can get it out without ripping up the threads keep the old. but you can get a new one for like 60 bucks. at oxygensensors.com i'v used them a few times. also why not get a highflow cat and some o2 spacers so you don't get the cel.

Si_chRis

I'd like to go high flow but I've heard numerous stories of them failing prematurely and the "honeycomb" element inside the cat breaking apart sometimes.

Thanks for the site for 02 sensors, I think I am going to get a new sensor along with the cat just to be safe...And to add it will be a pain to take out the old one since I don't own a 02 sensor socket.

z6hatchboy

If you dont have a code the the o2 you dont need to replace it, however its a good idea and cant hurt anything. Hit it with penetrating oil the night before you change it though, they can be a pain. o2 sockets are nice but ive never used one, just a open end wrench all the time

Si_chRis

Thanks for the info. I think I'm gonna pull my whole B pipe at once since I also just got a new exhaust system sitting in my room. Once I get my new cat, I'm going to bolt it to my new B pipe along with the new 02 sensor and just put it all in at once.

Also, where is the plug located for the secondary 02 sensor? How do I access it? I've heard that it's under the shifter/e-brake area or is it somewhere else?

z6hatchboy

im not sure where its at as im obd 1(eg), so i only have one. Just get under the car and see where it goes, it shouldnt be hard at all to get to

Si_chRis

Oh I see. I guess I will just have to find out when the time comes.

Anon51

yea your second o2 is actually under the area where the cup holders are. give or take a few inches.

Si_chRis

So I just pop off the center console and it should be there somewhere?