Toyota Tundra 02 cat converter

code keeps coming up for my cat converter and what should I check to make sure its the cat??P0420

 

Remove o2’s and Ohms test them. You can replace all 4 for under $200 if needed. Maybe someone can pull up the Ohms spec from the FSM?

 

Its probably your cat... my 02 Celica kept getting the p0420 and I ignored it for ages and would reset it before smog checks and would usually pass, until last year where it wouldn't stay away and I ended up just replacing the cat and its been gone ever since, pre cat O2 sensor is about 12 years old I changed it when the code came on and it still came back, post O2 sensor is OEM, or 18 years old.... My 07 Tundra's O2 sensors haven't been replaced and are 225k and 13 years old... for comparison...

 

4.7L or the 5.7L on your Tundra?

 

5.7l

 

Yeah. The 4.7L seems to be funky on the o2’s. I’m on my 4th set on the fronts due to CEL’s. 2nd set on the rears which never threw a code but were out of spec @ zero.

It probably is the cats but the o2 Ohms test is free. Sometimes we get these cat questions or people buy new cats because of the 420 and it doesn’t fix it.

 

Agreed, I threw in my Tundra, because its a Tundra forum, but I was explaining my 2002 Celica, which I do believe have the same O2 sensor and similar cats as his 02 Tundra...

 

I watched the downstream O2 sensor graph using my bluetooth ODB2 scanner and the Dashcommand app on my smartphone. It did not look like it should with a properly performing cat (based on some youtube videos I watched) so I replaced the cat with a bolt in Magnaflow replacement and the P0420 has been gone for a couple years now.

 

You can always swap downstream 02 sensors and see if the problem moves to the other side or not. If it tracks, it’s the sensor.

Or just wait until the check engine lamp light blows out. lol