Threw a code...

P0420 Something again with my bank one o2 sensor. Guy said either the sensor or the cat. If its the sensor then toyota will replace it for free since I already had it replaced not to long ago by them but if its the cat then what do I do? Can I remove my first cat and transplant my 2nd cat since its a cali truck in its place and just run one cat? Is there a cheap way of getting rid of my cats all together?

 

I had it too, and I changed my front AFR sensor and then cleared the code, but it came back about a week or so later. And a buddy of mine who is a machanic said that I should have changed both sensors at the same time. So I did the rear sensor then the code CEL never came back.

 

P0420-Catalyst System Efficiency below Threshold

 

sometimes its bad fuel, go get a fresh tank of premium, disconnect the battery for 15 min, and if you really want to pull the plugs and brush them off, worked for my moms expedition

 

X2 Thats what caused mine. I put on a tubular manifold for a 01+ 2.7 and no more CEL. Exhaust leaks at other places before the O2 sensors could also cause the problem.

There are several things that could cause this code. Before you spend the money for a new cat, do a little more investigating. From the threads I've read, the cat is the least likely to be the cause.

 

I had that code a little while ago and it was an exhaust leak. Check the simple things first. Mine was a leak between the 2nd cat and the rear o2 sensor.