hello all

the other day my check engine light came on and i had the code read at autozone. it was the P0420 code indicating a bad cat. i dont notice any weird smells coming from the car when running or anything of that nature. I am going to pull off my cat tomorrow and give a look see if it is still intact.

if it is still good i think i would just need to replace the second o2 sensor. why is that one so much more expensive than the one in the exhaust manifold? what is the big difference.

I have a 98 civic ex with manual transmission and 209k miles if that helps with diagnosing what is bad.

thanks!

 

If you have an EX then you have a D16Y8 SOHC VTEC and the primary O2 sensor is in the downpipe BEFORE the cat. If you have the primary O2 sensor in the exhaust manifold then you have an LX (D16Y7).
Best place I have found for O2 sensors is
http://www.oxygensensors.com
or
http://www.sparkplugs.com