Hey, i have a PO420 code, i know what it is but I dont know where it is located on the exhaust. Catalyst System Efficiency Below Threshold (Bank 1). Any help would be great to where it is located.

 

i believe that is the precat o2 sensor. Probably time to change both of them out if they are old

 

Along with the plenum and cat.

 

So the o2 sensor before the cat converter? I think there are 2 of them right?

 

No, dodgeboy1979 is incorrect. It is the post-cat sensor. And to answer your question, yes there are two sensors in a non cali emissions truck.

 

Jamie, is your cat hollowed out by any chance? My cat is gutted and I occasionally get the P0420 code because of it. If I don't clear it myself it usually goes away after a while. If your cat isn't gutted, it may be getting plugged. 90% of the time it's the cat at fault, not the O2 sensor.

 

My code doesnt go away unless i clear it and I am trying to figure out where behind the cat converter is the bad o2 sensor since it is the Catalyst System Efficiency Below Threshold (Bank 1).

 

Should be shortly behind the cat. If it isn't there.... that would explain a lot. Shouldn't be more than foot or so away. Might be on top of the pipe.

 

A 420 code is the one before the cat.......

 

P0420 1/1 Catalytic Conv Eff

Wonder if it is referring the cat, or the sensor..... not what I would really expect to see for a failing O2 sensor.... but then, it IS a dodge.....