P0420 Code Can’t see what else it could be?
 

https://cimg1.ibsrv.net/gimg/www.cam...d9e57b54c3.png
02 sensor data


See attached photo. Spike you see is from me giving the car max throttle…I have new 02 sensors and manifold. I believe the data is correct from my research. I just cleared the codes for a 3rd time, p0420 came back twice now. Am I missing something? This is a 2010 Camry with 322k miles on it lol

You are on the right track to check sensor wave forms.

Toyota has a very detailed service procedure for this code. hey have a website where for $20 for 2 days, one obtain detailed P0420 service info on the car plus any service bulletins. It may be possible to find the official Toyota procedure on the internet for free. Search under the code and engine model.

For some years of Toyota, it has happened a computer software issue can can this code. A service bulletin could reference this problem.

https://techinfo.toyota.com/techInfo...arch_docs_page

If you replaced the first converter there is a second that can cause issues.

Also check for exhaust leaks and make sure the engine A/F ratio is not in excess.

If everything on the car is OK, the code is normally related to a converter problem.