Code P0430

[cnl390]

My 2006 V6 Limited is giving me a P0430 code, which it looks like could be any number of causes from not too expensive to mucho.
I was wondering if there is any way I can narrow down the cause so I can determine if it is something I can fix, or if I need to take it in.
There seems to be no difference in the way the vehicle operates except that the warning lights are on. The last time I filled up there was a drop of about 1-1.5 mpg, but that could have been my driving.
Thanks in advance for the help.
Charles
P.S. I tried a new gas cap, but the lights are still on.

 

[CXS]

It's probably a bad O2 sensor from my experience, not too bad depending on whether it's upstream or downstream. I replaced mine without testing them and it fixed the issue on my V8. Just make sure you get the right one and don't go cheap and you'll be good for years ahead.

http://chrisin.co/index.php?p=pages&title=toyota-error-codes

 

[meonard]

P0430 is the bank 2 catalytic efficiency code. A simple (yet inconclusive) test is to use an IR temp gun and test the exhaust temp on the inlet and outlet of the cat. You should have a significant increase in temp of the outlet of the cat. If you do then you can start looking for other causes such as downstream O2 sensors etc.

Compare the readings to the other cat. If you need a new cat I highly recommend an OE replacement VS aftermarket. Cats are expensive so make sure you have completed proper diagnostics prior to replacement.

This is a fantastic video on the subject and the issues involved.

https://www.youtube.com/watch?v=vyVnhCIMDnw

 

[cnl390]

When I was driving yesterday just around the time my gas gauge went to under 1/2 a tank all the lights went off, and they haven't come back on. At least not yet.
Does this point to anything?