Thanks for the reply!
I checked out the video you linked but I’m afraid the results didn’t bring me much clarity. I tried both methods Eric demonstrates and seemed to get different results. I used my scan tool to check the live data from the 02 sensors and the upstream sensor oscillated rapidly as Eric shows in the video while the downstream sensor pretty much hung consistently around .8 volts. It moved a little but the changes were slight and not rapid – much closer to how Eric shows it on the Odyssey rather than his Subaru.
I also tried using the temp gun to check inlet and outlet temperatures. I recorded very similar temperatures (between 400-500 degrees) at the inlet and the outlet. However, I’m not totally sure of the validity of these results as on the Equinox the catalytic converter sits right up under the exhaust manifold tucked back agains the firewall i.e. it’s very difficult to get a temperature gun in there and be sure that you’re getting a reading off of the inlet of the catalytic converter and not off the body of the converter itself, a heat shield, the exhaust manifold, or something else in the vicinity.
I’d hate to replace the converter without verification but I’m not sure what else (other than the 02 sensors I’ve already replaced) would cause the P0420 – especially given that I know this vehicle suffered from oil consumption issues in the past.
Thanks for the help in walking me through this!