code po420 on 2000 Toyota Corolla

how to check to make sure cat. converter is bad

4 answers 1 comment
Typically you will have a Check Engine Code P0420 or it will rattle, especially in the morning. The code P0420 is common for the 1.8 lire Corollas. see the link below.
how can i check to see that the cat converter is not bad?
I have problem on codep0420
check for p0420 TSB! get toyota to reprogram it. they'll charge ~$100 but cheaper than replacing the Cat.
check back pressure with gauge