btrim23

This code pop out of a 96 Civic Dx. I have went into search and found that the code is for *the catalyst system efficiecny below the threshold. What could you do to prevent this code from poping up as an engine check light?

Opinions given was: Bad o2 sensor. Please help me on this so that I can pass the inspection test in NC. Thank You all.

jlacoy82

Replace o2 sensor, if no help, replace catalytic converter.

B-twentyVTEC

code p0420 means the catalytic converter is not efficiently doing it's job.
possible cause internal deterioration or a crack manifold. Replacing the O2 sensor will not fix the problem.

delslo93

yep change cat

uRizen

How does the system measure the efficiency of the cat? I've gotten the code before, but it's erratic (seems only on the coldest of days, which makes sense).

Theoretically, if you gutted the cat, would it still throw the code (*cough*cheap-****cough*). :D

btrim23

I think it will throw the code if the cat is gutted. My friend owns an 98 accord, decided to gutted his catalytic converter, and now check engine lights is on. I'm sure it's that.

* Thanks you guys, I guess I'll get a new o2 sensor to see if it work, if not then I'll refund the money and get a new catalytic converter.