P0420 Code

Trying to get my P0420 code to go away. I am going to start checking for any leaks and replacing the O2 sensor. Is this the left or right side downstream o2 sensor? 2005 sr5 v6. Rockauto has Denso sensors, these ok to use?

 

Passenger side
Denso o2s are really good.

Chances are you are having leaks or a bad cat. Join the club. Lol

 

220K on the original sensor. guess it can't hurt to try.

 

Save the old one. Unlikely to be bad. You could test it if you can read the readings off the pcm via a scan tool etc

 

https://www.youtube.com/watch?v=i_X6sW6hldw

 

I swapped the sensors side to side (cable is diff length, but it worked after releasing from support). Issue did not follow the O2 sensor. Took it in and I had a bad cat.

 

I had the P0420 monthly on and off. I changed the PCV valve and it's been three months since the light came on. OEM PCV is cheap $8 or less....I also bought the cheater fowlers but my 02 sensor was seized so I haven't gone that route. Good Luck!

 

Maybe you tried this, but I had to soak one of mine for a couple days with PB blaster and then finally ran the truck to get it nice and hot, and I was able to break it loose.

 

This is my issue. Currently its off.

 

At the mileage, its common that the cats are just bad. Throw a o2 sensor spacer on the rear o2 and you will be good to go. Thats what I did for a while. Ended up just putting long tubes on and getting rid of the cats all together