P0420 code. How do I fix it??

[manybrews]

if you have no cat, the light WILL come back on.
you will need to replace the cat if you have any hopes of this issue being rectified.

[paco]

thanks for the quick response manybrews. Do you think a high flow cat will do?

[cdaw2001ES]

IMO Thats your best option, you have to have an 02 bung added after the cat. This usually means you also have to extend the 4 02 sensor wires. And plug up the stock - now unused o2 bung.

Or just get a new stock sub assembley

Does resetting your ecu - make your lite come back on (pull the negative battery cable off for 20 mins)

[MASONSTORM]

no such code po442, dont exist. lemme look at it. I work at mitsu.