Hey guys,
About 6 months I got the 420 code and took it to the dealer to have it reprogrammed under emmisions warranty.
It was all good until about a month later when the wife put in regular. The light went back on and I took it to autozone who cleared it.
Then a few months later it went on again using the regular....after running premium through two tanks it went off by itself.
Then for the hell of it I put in regular and it went on again. Now after a few fill ups of premium it hasn't gone off.
I went to autozone and they told me they think I need a new cat since the code still goes on after the re-progaram from the dealer..

Do I need a new cat? how can i tell other then the light? does this sound normal...at all?? has anybody else had this experience?

one more thing...before I took the car to the dealer I took the car to a trusty mechanic who pulled the code (cost me 70bucks) and told me it was a system error because there is nothing wrong with the cat...but that was 6 months ago.. I always trust mechanics who tell you the piece is not broken...

Thanks in advance.
Mike

 

Get used to it.. the should change the Maxima name to PO420.. I have the same code.. it comes and go... I actually miss it when it is off.......

 

I have had it for a year and half.

I bought a obdII scanner just to erase it from time to time.

Now I just leave it on all the time. My car runs better with when it is on, than when I erase it.

 

Get an 02 Simulator. I had that same code for about 2 years then finally got the 02 simulator and the SES light hasn't come back. Main reason I bought it was b/c I had to pass emissions. My car actually runs better with the light off.

 

Thanks guys for all the replies. The SES light just really annoys me...my last car was a 89 legend...never saw a light in the 6 year I had it...it was stolen last october... :-(
Plus I am worried I will just ignore the light and then something really bad will happen like a coil...

y2KAOSMax: What is a 02 simulator?

RobR and Lontar1...Thanks for the replies...I knew we all had PO420 issues but I did realize the thing just stayed on...and yes they should call it a Nissan PO420...
and yes Lontar1 I also miss it when its off...it makes my dash look wierd without the little light...

oh well. my next ride is a GS... (thats a dream..)

later.
Mike

 

You're on the same path as me. My next car will be the new GS also.

You can get an O2 simulator here... www.o2simulator.com/24803.html

It tricks the car into thinking the O2 sensor is working fine. Only costs $30. Real easy install too. Works like a charm.

 

I took my car into the dealer to try and get some more information. 100 bucks later they told me that the catalyst in the pre cat pipe (before the main cat) was burning up and particles were triggering the after o2 sensor. They cleared the error and I, so far, have not seen it again. They wanted to charge me $1200 to replace the pipe! Sheesh, that's ridiculous. I wish Nissan would put out a recall. I mean come on, the emissions are fine, it's the frigging emissions detector thats burning up and triggering an emissions error. What the hell is that?

 

you guys shouldn't get this mixed up

2001 maximas are all cali-spec so the P0420 code falls under a TSB for updated ECU software (www.nissan-techinfo.com)

2000 maximas do not apply to this, so it could either be the o2 sensor or the catalytic converter which will have to be diagnosed with a consult-II at the dealer.

I don't like any lights on in my dashboard that shouldn't be. I've had both my 2001 ECU's reflashed for the P0420 tsb.

 

Good point on the different specs Larrio. I have also had my ECU flashed and the light still comes back every couple of months.



I'm curious Y2kAOSMax. Would that o2 simulator work for the rear o2 sensor on a Cali spec? Heard of anyone who has replaced it?

 

Yes. They even give you a money back guarantee. It'll work on any O2 sensor. As long as you know which one is causing the problem. Not having the SES light on is worth the $30.

 

i have the o2 simulator, dual version so you can use it on bank 1 or 2 secondary o2 sensors

 

I had got the same code and had the Crapalytic converter replaced and the code has been gone ever since.