My check light came on a couple of days after having my car inspected. It passed on 2002 Lexus GS300

Emissions test. I took it to Auto Zone for a printed diagnostics test. The code P0430 came up. Is that the o2 sensor?

Asked by for the 2002 Lexus GS300
could be o3 sensor or cat converter.mech needs to inspect o2 readings to determine which parts are bad.