[kaos_kryptonite]

A few months ago my check engine light came on. The pictures attached is the code readings. So I live in SoCal and its time for a smog check. The code I'm currently dealing with is P0420. I tried a lot of different things that I have looked up. These are the things I have tried. I have cleaned the mass o2 sensor, replaced PCV, replaced spark plugs, cleaned the bottom o2 sensor. I'm really trying to avoid having to replace my catalytic converter. how often you have to change catalytic out? Anyone have any feedback or suggestions.

 

[kaos_kryptonite]

I also replaced all air filters as well.

 

[Easy Rider]

My guess is that with 140K miles it might not be unusual to need a CAT replacement.

Two things though:

I see it is complaining about low battery voltage too.......and a low/weak 12 V battery can give erroneous failure indications on ALL KINDS of other things that really aren't bad. So I suggest that you first test or replace the 12 V battery and check the charging voltage.

Then, if it ends up that you do need a CAT, do some shopping around.
I think you should be able to find one from a 3rd party company for half of what Toyota wants.....or even less maybe.

P.S. If you disconnect the battery and clear the codes, don't think you can run right in and get it tested.
The system logs that recent reset and sometimes you have to drive it a month or a thousand miles to allow for a good test.