is obd2 code #p0420 cat related or sensor related and i on 2000 Toyota 4Runner

i replaced both 02 sensors about 5 months ago ck eng lite came back on about 1 month ago what now?

by in Durango, CO on July 15, 2012
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1 answer
ANSWER by , July 16, 2012
this could be alot of issues but the catt's are 12 yrs old, get a diag and est