2001 4runner , new to forum, new to 4runner's P0420 problem

[danielzak1990]

Hello everyone,
I just purchased my first 2001 toyota 4runner SR5 3.4L V6, im from toronto ontario canada. I need to do emission test to transfer the vehicle over, and i get a
P0420 code , catalyst system efficiency below threshold bank 1
From some research i did i cane to conclusion it could be
O2sensor or catalyst converter , i have not been under the car yet to further diagnose. I have attached a picture of the code and a video of the live 02sensor data at 2500rpm.
Please help me resolve the issue so i can enjoy my 4runner

https://vimeo.com/117443623

 

[danielzak1990]

One thing i did not mention, i cleared the code twice now and both times it comes back about 24 hours later , in the cold weather on the way to work in the morning.

 

[Ammomac]

gotta admit - when I saw a "po420 problem" I was thinking something entirely different. ;-)

 

[danielzak1990]

Ohh it took me a while to get what you wrote lol.
Can anyone lead me in a right direction? Can i do anything to further disgnose the cause of this code ?

 

[xspsi6]

Replace o2 with oem denso and it will go away. Easy fix

 

[danielzak1990]

Which 02 sensor? Front or rear ?

 

[TheDurk]

Either sensor can cause a P0420, but the rear sensor is the by far the more common cause of the two. Front will usually throw other codes first.

You should eliminate another common cause: any exhaust leak before the rear sensor all the way to the manifold. Factory exhaust gaskets are turning to dust at this point, and a slight exhaust leak can provoke a P0420. Mine was leaking just before the rear cat at the flange. $4 fix for new gasket.

 

[danielzak1990]

Thank you [MENTION=10169]TheDurk[/MENTION] , i will be checking it out today and i will let you know. The truck is new to me and i have not been under it yet, i do know the previous owner did have issues with the flange at the cat you speak of.
Thanks for your help