What's the downside of o2sim to fix p0420?
 

Just bought a 2001 maxima and of course on the ride home the CEL lights. Read 2 P0420 codes and cleared them. Keep coming back and I need to get the car inspected here in NY.

Will using the 02sim dual from 02simulator.com have any adverse effects on the engine, the exhaust system or cats?

NONE the o2 simulator helps the ecu show that the cat is functional
if you have emmisions in your state they may check it but i dont think it will effect it
call brian at cattman
he can explain it to you better then i can
but i ran it HARD for months without ever having the light come back on

Thanks. I didn't think about the emission inspection picking up the o2sim. Here in NY they connect to the OBDii and read readiness.

The only downside, aside from an inspection where they will see the o2 sim (most inspection stations on cars with obd2 will just use the obd2 port) is that you know inside that you are "polluting" the world...