P0420 - Catalyst System Efficiency Below Threshold (Bank 1)

[tmkuruppu]

Hi Guys,

The following error comes in my Toyota corolla 2006. I have attached live data of O2 sensors and others.  What could be the issue here? Do you think there may be a faulty oxygen sensor? Or the catalytic converter should be replaced? Or any other reason?

Appreciate it a lot if you could help me at this time cause the check engine light is still on. 😟

[FK141]

This is a very common problem with Toyota cars if the amount of videos posted on YouTube is anything to go by. Have a look at them and you’ll get a good idea for a course of action or multiple actions.  You can use an OBD tool if you access to one to reset your code and it will stay away for a while. It takes a certain amount of drive cycles for it to show again if you don’t do anything to fix it.