p0430 code

ok, my CEL came on and it threw a P0430 code. I changed both pre-02 sensors (have not done post 02's yet). Reset code, after 200-300 hundreds miles the CEL back on and it still throwing P0430 code. Is it my CAT or should i try replacing the post 02 before looking into a new CATS? Car runs fine, pickup is strong going up hill. Sometime when i sit at idle, i feel a little misfire, but goes away immediately.

thanks you guy.

P0430 - Catalyst System Efficiency Below Threshold (Bank 2)

Bank 2 is the post O2 readings are not what is expected. Try checking for exhaust leaks or changing the post O2 sensors before changing the cats. Normal wear on cats is more than 130K. But I have to say that in a couple of cases a cat change or a tune-up cleared the issue.

i will try that. thank you kindly sir.

I am showing this error too. Did changing the post o2 or cats have any effect?

Tap the cats with a rubber mallet. If they rattle, they're done. Mine finally went out at 125k, and got so bad the the right side caused multiple random misfires (due to increased back pressure).

I installed 50-state CarSound cats, new O2 sensors, and I can't remember when the engine has run this well.

Did you replace the post-cat o2's AND the pre-cat o2's or just the post-cat ones?
Thanks!

Originally Posted by edjack

Tap the cats with a rubber mallet. If they rattle, they're done. Mine finally went out at 125k, and got so bad the the right side caused multiple random misfires (due to increased back pressure).

I installed 50-state CarSound cats, new O2 sensors, and I can't remember when the engine has run this well.

Cannot find 50-state carsound? Can you provide the link? My 2003 X5 has code P4030 and I replaced post O2 sensors but did not fix. Do you know which side is bank 2?

Just and update for my car. After I had the catalytic converter replaced with AP one, the code went away. The cost for AP converter was $160 plus $40 installed. The shop installed the converter for me was
http://www.performancemuffler.net/

Not bad at all.

Hi, I know this is an old post but I am dealing with the same faulty code P0430 cat efficiency bank 2 with my 1999 540i e39, but I have changed anything yet, as u said u change the cat for $160 plus $40 labor, I would to know which cat you changed all the 3 or just 1 I know mine has 1 cat in the front and 2 going down each side.
Thanks