[Strange246]

Hi all, first post here, been lurking for a while, cool site with lots of info...I have an 03 Durango, 4.7L, 117,000 miles, I recently replaced the exhaust from the manifolds back (and the driverside manifold) with a Dynomax system, also I replaced the O2 sensor on both sides of the converter (Bosch from Napa) since then the CEL has been on, its spitting out this code:

P0420 (M) 1/1 Catalytic Converter Efficiency Catalyst 1/1 efficiency below required level.

I've checked and double checked the manifolds to verify no leaks, I've reset the CEL twice and within 120 miles its back on, WHY??? I've read that the Bosch 02 sensors are not the best idea, they say to go with Dodge sensors only, any truth to that? I'm at a loss and have a week to sort this out and get an inspection sticker, any help would be most appreciated!

Ryan

 

[l1tech]

Did you remove the cats???

 

[Strange246]

The cat is brand new, the whole Y-pipe from Dynomax comes with it...

Ryan

 

[99Dakota]

sounds like a bad cat or a cat thats a little too high flow for the trucks emissions parameters.

and yes, bosch O2 sensors are garbage.

 

[bwdakrt]

Check to make sure you have the O2 sensor connector plugged in all the way on the drivers side before the cat. Sure you got the right O2 sensor? Part # should be BSH13610.

 

[l1tech]

There is a better than average chance that the cat that came with your kit isn't up to the task...and yes Bosch O2 sensors are the worst thing in the world.

 

[Strange246]

Thanks folks, I'm going to check the intake and output temps of the cat. converter first, I've been told the temp difference should be atleast 100* or the cat has to go...

 

[l1tech]

Taking cat temps is the worst way to tell if the cat is operating or not...too many variables involved that can throw the temps off. You could have a cat that is working but not to the potential that the pcm is looking for, in that case you may have your temp difference but it still isn't doing enough. Chances are as long as you don't have any oxygen sensor codes then you have a bad cat.

 

[Strange246]

Taking cat temps is the worst way to tell if the cat is operating or not...too many variables involved that can throw the temps off. You could have a cat that is working but not to the potential that the pcm is looking for, in that case you may have your temp difference but it still isn't doing enough. Chances are as long as you don't have any oxygen sensor codes then you have a bad cat.

The only code is the P0420...

Ryan