Trying to wrap my head around fault code P0430 and P0420

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Originally Posted by KRAM36

How many miles do you have to log for the CEL to come back on?

I just put 57 steady cruising miles (no wot) from 45 to 74 mph on the car and no CEL yet.

Maybe a few drive cycles. As I understand it, the best way to clean out partially fouled cats is to take a spirited drive and get them nice and hot. This oxidizes contaminates and improves cat efficiency.