I've changed the cat, downstream o2, and resonator. How long before it clears the p0420 code?

Question

Or do I just have to disconnect the battery to clear it myself and drive 50+ miles for it to register all sensors again? The reason I'm asking is my temporary plates have expired already due to the expense of the parts.

Answer 1

you have to disconnect the battery until the code clears. Sometimes it may take 15min if that does not work disconnect the battery overnight or a couple of hours.