01 Avalon. 3 catalitic converters and how to deal with them

[car5car]

One converter is in front exhaust manifold, second is in pipe under oil pan (for rear head). Third one is common for both heads. First and third are visible, so there is no problem to see if they are OK or not. Maybe if you remove first and second converters car will still pass emission test. If you have converter code it is probaly nothing to worry about if converter is not clogged. If it is clogged remove it using long screwdriver (removing converter is illegal, that means it is legal to have clogged one!). I am not sure how to diagnose second one, it is invisible. Pipe under oil pan has actually 2 pipes(one with converter, another one w/o) so you can blow in each from front and check if you feel the same on another side of each pipe.

[Nad1370]

Toyota converters rarely clog up.
If you want to diagnose a clogged one.
Your first clue would be lack of power.
Motor running hotter than normal. Temps might go up.
Running richer than usual.

You'd likely get a P0420 code than having your cat clogged up.
Oh yeah...driving with a clogged converter is not illegal. I just asked my bro. in law who is a cop.