02 Toyota Solara CEL code P0420

Just purchased a rather nice 02 Toyota Solara. Will need to pass emissions test here in Ontario to licence the vehicle. Seller was upfront about the vehicle perhaps requiring a catalytic converter. Had the codes pulled and the only code is P0420 bank 1 catalytic converter efficiency below threshold. Car runs perfectly, the fuel economy is very good and tbh I’d rather not replace the converter if it’s unnecessary. I’ve read that code is rather generic. Could be a bad O2 sensor, or bad plugs or a host of different things. I reset the CEL light but it returns rather quickly. About 15 min of highway driving will trip the trouble code. If not for the necessary emissions test frankly I’d just ignore it but alas I need to pass the test. Any advice greatly appreciated.


Oh my bad. It’s the SLE model with the 3.0L V6 engine.