Check Engine light came on.. code said it was the Cat help!

[bhouse1587]

ok so while i was driving down the highway my check engine light came on and i stopped at autozone like 2 days later to have the code read.. said it was the cat.. now i do not want to buy a 250$ thats a replacement, i was thinking about going with an exhaust what are my options? what is a good cat that is not gonna cost me an arm and a leg.. and the only mods i have done to the engine are the throttle body bypass and the CAI.. thanks in advance!!!

2002 elantra gls
5speed

Tim

[Pete03GLS]

well... if its a bad cat, replacer it. if u want an exhaust... ull probablu end up getting rid of it, if u buy a premade one. if u make an exhaust ur self, u can put new high flow cats in or something.

[DJ Hellfire]

You can't really just go with an exhaust in this case. The cat that would cause this code is the first one which is part of the exhaust manifold. So if you want to do an exhaust and fix this problem at the same time, you'll need a header, cat back set-up, and move your O2 sensors to the front and rear of the second cat. You're talkin a lot of money in one shot, a lot more than it would be to just get a new stock manifold/cat. But if you plan on doing the exhaust anyway, go for it.

And how do you know it said it was the cat? What was the exact code? The only code that would point to a bad cat is a catalyst effiency code.

[bhouse1587]

im not sure on the exact code, i will go back tomorrow and find out.. so there is 2 cats?? one on the header and one on the actual exhaust pipe? ive heard something about a soundcat or an OBX cat as a replacement, anyone know anything about them..

and yea i wanna jsut do the whole thing in one swoop, like header, catback and muffler what is a good setup for our beta 2.. im not planning on ever turboing or ss, maybe just more internal upgrades to make it more NA.. THANKS GUYS!!

also whats the worst thing that will happen if i dont replace it like asap.. i mean other than not passing emissions which i was lucky to have just passed 2 weeks ago :D

[DJ Hellfire]

1. im not sure on the exact code, i will go back tomorrow and find out.. so there is 2 cats?? one on the header and one on the actual exhaust pipe?

2. also whats the worst thing that will happen if i dont replace it like asap.. i mean other than not passing emissions which i was lucky to have just passed 2 weeks ago :D


1. Yep, one that's monitored by the downstream O2, and one that isn't.

2. The worst that will happen is that you will polute the environment. The cat could also break apart inside and/or choke the **** out of your engine!

[krodammi]

not to mention suck the crap out of your gas mileage!! its prob P0420 which is what i've been running for like 6 months. its much better if you just get it fixed rather than put it off. gas is just too damn expensive

[judys01GT]

i just got P0422 main catalyst below threshold, does that mean i need a new cat too.

[bhouse1587]

yea the code is p0420 but im not losing gas mileage im still close to 27MPG with a mix of highway and city

ok so guys that have this code try this..

at about 1/2 a tank put in a bottle of HEET and run your car until its almost empty and then pull the NEG terminal of the battery and hold the brake for 15 seconds to clear the computer.. plug in and see if your light is still on.. i did this and my light turned off and is not showing a code anymore.. :D