Threw Codes P0420 and P0430

themaildude · 09-05-2009, 07:27 PM

P0420 catalyst system below threshold (bank 1)
p0430 catalyst system below threshold (bank 2)

Had my SES light come on going to work last night. When I hooked up Cipher I had these two codes. I Just reflashed my ECU with a new tune from Uprev a few days ago and am wondering if this may have caused the codes. I just cant see both Cats failing at the same time. I have the Magnaflow Hi-Flow Cats and Nismo Headers. Gotta get under the Truck tomorrow to see if there are any exhaust leaks and I'll hit the cats with a rubber mallet to see if I can hear any thing rattling loose in there. If anyone has any ideas what to do please chime in. I did clear the codes to see if they will show up again, hopefully it was just a glitch with the new tune. Truck is really running nice otherwise.

gtxracer · 09-05-2009, 09:39 PM

My truck threw these same codes tonight. I went to Autozone and had a real wise guy tell me the codes and gave me good suggestions. He's been around a lot of cars and knew what he was saying. Told me he really doubts both cats went out (like you) and to replace my plugs. Yeah, NGK plugs are great but they can go out. When did you change yours last?

He also recommended a fuel conditioner. I believe its made by Lucas but I can check to be sure. I lent my truck to my cousin and she might have put some bad gas in it. He also said the seal on the gas cap can go and throw codes so he recommended I check it and make sure its tight.

Other than that, I cleared the codes and hope it doesn't happen again. Truck still runs great and is almost 100% stock. Has a K&N air filter, oil filter, and full Castrol synthetic so I know I take care of my stuff. He also said it could possibly be my fuel filter or PCV valve but possibly not too.

themaildude · 09-06-2009, 05:46 AM

Thanks gtxracer good info there. I have driven about a hundred miles since I've cleared the codes and they haven't come back. I did reseat my gas cap.

gtxracer · 09-09-2009, 10:42 PM

Mine came back on yesterday. No performance changes at all, still got power, still running solidly. I think the manifolds might be going and I'm under 80,000 miles so I'm going to take it into the Nissan dealership downtown and see what they can do for me. I find it easy to suspect its the manifolds or cats since NGK spark plugs don't go out very often (and that wouldn't cause both banks in my opinion), it's still getting fuel, and a large random vacuum leak doesn't seem probable - unless it's the headers!

What do you think?

**layer1** · 09-10-2009, 04:55 AM

You two guys need to search the forums for these codes. There're several threads discussing these codes. If you both are running long tubes you were running lean. Jared just added more fuel to bring it back into spec, thus causing your secondary 02 senors to throw these two codes. Before going on please outline to us your exhaust configuration. Shorties/Long tubes, HF or Stock CATS, did you have 2 or 4 CATS before putting the headers on, have you moved your o2 sensor behind the secondary CATs, etc.

Not raining on your you posts here but there are several threads discussing all of this and you would have known to expect these codes. Also, Im late on having my first cup of coffee this morning.

Post your exhaust performance and someone will chime in and let you know what you can do. Without knowing what you have do MOD wise its hard to assist.

gtxracer · 09-10-2009, 11:53 PM

I did search. Every thread is about trucks with mods. Mine has none. I run a K&N air filter and thats the extent of my "mods". I still haven't installed the PRG leveling kit I bought months ago because this is a commuter and parts hauler for me.

It's a stock '04 KC XE 4x4. No headers, no intake, no mods to the system. I didn't do anything to the truck prior to this code. It ran fine and still does. If anyone can help me before I go to the stealership on Monday I'd really appreciate it.

-Trevin

themaildude · 09-11-2009, 03:07 PM

Quote:

Originally Posted by layer1

You two guys need to search the forums for these codes. There're several threads discussing these codes. If you both are running long tubes you were running lean. Jared just added more fuel to bring it back into spec, thus causing your secondary 02 senors to throw these two codes. Before going on please outline to us your exhaust configuration. Shorties/Long tubes, HF or Stock CATS, did you have 2 or 4 CATS before putting the headers on, have you moved your o2 sensor behind the secondary CATs, etc.

Not raining on your you posts here but there are several threads discussing all of this and you would have known to expect these codes. Also, Im late on having my first cup of coffee this morning.

Post your exhaust performance and someone will chime in and let you know what you can do. Without knowing what you have do MOD wise its hard to assist.

All my mod are listed in my signature. I was actually running a little rich and Jared leaned out my tune, that's when I had the codes come up. I have driven close to 300 miles since I cleared them and the have not returned.

themaildude · 09-11-2009, 03:51 PM

Quote:

Originally Posted by layer1

Not raining on your you posts here but there are several threads discussing all of this and you would have known to expect these codes. Also, Im late on having my first cup of coffee this morning.

I always try searching first but came up empty, can you give me some links to the posts you are referring to. Thanks

BNissan · 09-21-2009, 07:34 PM

Maildude,
I pulled the same two codes on my truck, which is almost stock (Volant intake, Flowmaster muffler). I had the stalling out/trouble restarting problem, which is what led me to the local auto parts store to get the codes pulled. Turns out the problem I was having was due to a faulty IPDM, which I've replaced. My next step will be to reset the codes and see if the same two come back. I'll post again with an update.

gtxracer · 09-21-2009, 10:21 PM

My code went away tonight. I'm not sure why or how but I do hear a slight ticking sound out of my fenderwell. I'm taking it in Thursday morning to see if they'll replace the headers or at least take a look.

gtxracer · 10-29-2009, 06:23 PM

Forgot to update this: My codes were from leaking manifolds (cracked). Typical stuff, dealer will replace them as soon as I get the truck into the shop.

[T.J.] · 11-01-2009, 05:23 PM

Quote:

Originally Posted by gtxracer

Forgot to update this: My codes were from leaking manifolds (cracked). Typical stuff, dealer will replace them as soon as I get the truck into the shop.

hey bud too bad i didn't see your post sooner.... but i can help get you straightened out now at least.

i have had the same problem 3 times. and you will have this problem over and over again if you just keep replacing the cats. the problem is the fuel pumps are faulty and don't send enough fuel causing your cats to melt down and throw these codes.

this last time my truck was in the shop for 3 weeks while the dealership tried to get the job covered under warranty. they had a hard time because this last cat only "cracked" instead of melting down like all the others.

but in the end they got it covered and replaced the fuel pump and gaskets all free of charge and no more codes or problems. so make sure you tell them to check you fuel pump or if they won't tell them to call Keith @ Jenkins Nissan in Lakeland, FL and he will school them on the problem if they don't wanna keep putting cats in your **** every 6 months. that's all they last for me.

gtxracer · 11-01-2009, 10:26 PM

I appreciate the help. I will write this down and take it with me on the next visit. Thanks again!