4Runner O2 Sensor Replacement (Fix for P0420!!)

I've been trying to track down what's causing my pesky P0420 engine code. Today we finally tackle to issue when we replace the downstream O2 sensor.
Thanks for tuning in!

[@jasonwetzstein5410]

P0420 is cat efficiency. A exhaust leak downstream of car will trigger this code or failed converter. Toyota’s are common for the downstream cat gasket leaking ( also pulling air in while exhaust pulse travels back to valve). Personally have never changed downstream 02 for “420 codes”. But would suspect old gasket

[@jonathanarthur3580]

Heat. Map gas torch or a shop torch if you have access and get the nuts cherry red

[@echopapa243]

The code is from the air/fuel sensor ahead of the CAT

[@echopapa243]

Pound a undersized socket on those nuts after they’re loose and ratchet them off

[@jasonwetzstein5410]

Sorry downstream oxygen sensor gasket leaking.

[@PartimeOverland]

Yes, very likely! Or could have been the sensor getting a bad reading. Either way, the sensor was long overdue for a replacement haha