I had a p0420 code a few months back leaving a CEL on. I have a 2k1 I30, anyway, I brought in the TSB for it and they confirmed that it was what was causing the CEL.
They told me that both o2 sensor and y-pipe were needed. I bought just an o2 and put it in and the CEL went away. Is this going to cause any long term probs because I didnt do anything about the y-pipe?

 

What specifically did they say was wrong with the y-pipe?

 

For the love of God!!!! SEARCH!!!!

 

I did search, before i posted and I'll clear up a little more info for you. First off, I had them check the ECM version, it did not need to be reprogrammed, secondly my car has 89k on it so I dont fall into the 8/80 or any other warranty for that matter. Thirdly I don't have the rotten eggs smell so I think the cat is fine. I know about the TSB and all of that parameters for it. I simply wanted to know if i should have any other issues b/c i did not replace the y pipe?

To answer scottwax, they just said it needed to be replaced. Nothing more.

 

Don't lie to me...

http://forums.maxima.org/showthread....ighlight=p0420

 

I'd ask them specifically why they feel you should replace it. Maybe the service manager has a boat payment due or something.

 

For your information i read that thread completely about 2 times over, this was well before I posted. I've had the code for about 2 months so I read everything in there. Thats why I was asking if only replacing the o2 would matter, someone in there said to do the y pipe and not the o2 but not the other way around.

 

My CEL recently came on with my 2001 AE Maxima with the code P0420. I was in luck for the 8 years 80k warranty (I had 76k miles on my max) so i took it in the "stealership". The mechanic check the engine with the consult and replaced my front tube assy. and O2 sensor per the service bulletin.

On the invoice it stated the cause was:

FD10AA RPL ONE FRONT EXHAUST TUBE 27 WARN
1 20020-3Y400 TUBE ASSY-
1 22690-2Y921 HEATED OXY
1 20692-65J00 GASKET-CAT
1 20691-51E01 GASKET-EXH
1 20691-38U00 GASKET-EXH
DE47AA RPL ONE FRONT EXHAUST GAS (O2) SENSOR

Nissan replaced all the parts above for free and my CEL went away and hasn't came back.

The bad news was from the free 27 point vehicle inspection it turns out that my alternator bearings is out and need to be replaced with an estimated parts and labor of 575 dollars. Which I have yet to fix yet, anyone has an idea on how to fix the alternator below 575 dollars?

 

I too had the dreaded 420 code. Took it to one dealership and they said I needed two 02 sensors (upstream and downstream) and said nothing about the y-pipe. Replaced only the downstream 02 sensor and the CEL came back on. Took the car back to another dealership and they said the cat in the y-pipe was shot and replaced the pipe for free under the 8/80.

Code went away and never came back

2 months later I replaced Nissans shinny brand new y-pipe with one from Warpspeed