2013 Code P0420 - tests?

Good afternoon all,

My 2013 Prius had it's engine light come on, with code P0420. Took it to a dealer to confirm. My question is - can anybody point me in the right direction as far as a guide or information on testing the O2 sensors as well or a way to diagnose this further? I just need to know what tests I can run to make sure it's the catalytic converter and not just the O2 sensors.

Thanks in advance.

 

You're absolutely right. Silly me. Downloaded a 2010 service manual so I should be good to go! Thanks!