Keep throwing P0420 Code

[Rebelord]

Yup, this dreaded code. Been reseting it off and on over the past year. Once cleared, sometimes will stay gone for a day, to weeks.

 

Now, yes, I know the code and what it represents. Just that the cause, is where I'm at a cross road.

So, my intake tube, does have some cracks in it, dont really notice them unless you move it in a way to "open" them. If they are leaking, un metered air can set off this code. I did call Rob out in Texas about the tubes, unfortunately I'd have to buy the whole intake system for replacements. Unlike the 3.3. where you can still buy the rubber parts solo.

Secondly, I haven't changed the O2 sensor, but I may try that first. Thoughts? BTW, this one will be a major PITA to swap out. =(

Thirdly, just say screw it and decide to replace the CAT and the O2 at the same time. Which, may as just do both sides, and call it a day for the next 150-200k miles.

 

Anyone else have fun with this code to offer maybe a trick to not have to spend a ton of money?

[vg33deguy]

This is cat bank one isn't it? Mine was a gasket at the top and bottom of the cat. I had this code off and on replaced those two gaskets and ran some cataclean when I replaced my knock sensor and it's been clear for 3 months now.

 

 

Sent from my iPad using Tapatalk

[Greg_C]

Well, I just started getting the code today, so here I am sifting through the rubble of internet info to try to get a straight line on what the root cause is.

 

I have a 1996 Pathy LE 4WD with 220k on it. I've replaced the O2 sensors. Those codes went away. My truck is sluggish going up hills (Phoenix to Payson or Prescott) and even worse when I have a trailer on it with camp gear. Any results from your discoveries would be greatly appreciated.

[mandersen8]

I had this code come on yesterday while wheeling. I also had one for the O2 sensor behind the cat.now I was think I put premium in the tank and was about 7 thousand feet in elevation. I also have 147k on it and was hopping this was not a big deal any thoughts?

[deltaR50]

id fix all the issues that would consider triggering that code. i had my system lean both banks for almost a year. gave me that code also. i trace all possibly cause and was able top fix them. then it cleared me that code

[Greg_C]

I had this code come on yesterday while wheeling. I also had one for the O2 sensor behind the cat.now I was think I put premium in the tank and was about 7 thousand feet in elevation. I also have 147k on it and was hopping this was not a big deal any thoughts?

 

So far what I'm seeing is the possibility of my catalytic converter being bad. Seems to be more of a problem when it really warm outside. If my truck stays warm, I'll have a serious miss when I start it back up. If it sits all day, and I start it after I get out of work, it's usually okay. But if I stop somewhere for 30 - 60 minutes after it's been driven and brought up to temp, it give me @!*%. I've replaced both downstream O2 sensors.

 

There's a way to check your cat with a pressure gauge using the upstream O2 port. Here's some links for you to consider. Pay attention to the symptoms. Some of the tools aren't very expensive. And I'll give you a link for a place on line to get parts.

 

https://mufflerexpress.com/products/nissan-pathfinder-96-99-bank-1-3-3l-v6-catalytic-converter

 

 

Let me know how it goes.

 

Greg