Help with P0430 code! O2 sensor Guru's step in!!
 

Hey all, I recently pulled a p0430 code for my max and did some research. It seems like the Bank 2 Rear (Sensor 2)(red wire) is at fault. The thing is I changed this O2 sensor out last summer for another code that came up. I originally thought that Bank 2 Front (Sensor 1) (blue wire)went bad because I havnt changed that one yet. Which one should I change? I read that an old "lazy" O2 sensor can cause other O2 sensors to go bad. Could it be that the old blue wired O2 sensor messed up my newer (red wire) O2 sensor?

Thank you

p0430 would be the pre-cat efficiency below threshold bank 2.

What makes you think you've got bad o2s?

Agreed, sounds like a bad precat.

The beginning of this thread directs the problem to an O2 sensor, but the last 2 replies speak of the precat to which you guys are talking about. http://forums.nicoclub.com/zerothread/344395

Where exactly is the pre-cat for this problem? Is it the main catalytic converter after the y-pipe? I have a cattman y-pipe on there. Or do I have to change the exhaust manifold for the front bank (front of engine)? Because from this thread, http://forums.maxima.org/5th-generat...bs-inside.html it doesnt look like there are any "cats" on the exhaust mani.

All help is appreciated. Thank you

your front precat(between the rad and motor) is most likely shot.
It's a bit pricey but should be fixed sooner than later

there is one pre-cat after each exhaust manifold then a third cat after the y-pipe. the cat after the y-pipe is not monitored. one o2 sensor before and after each pre-cat. basically the o2 sensor is there to monitor the efficiency of the pre-cats.

I don't mean to rob your thread, but I just pulled this code today as well. I was wondering that instead of replacing the bank 2 cat, would we be able to get an after-market part (headers for example) that would fix the problem and add performance?

How many miles on the O2s!! I had a P430 at 80K and the forum folks said it was the cats/pre-cats etc. Replaced all 4 O2s and now with 165K no codes, no nothing. Emissions #s definetly prove my cats/pre-cats are working just fine, they are designed to last a very very long time.


Start with O2s and go from there..

Nowhere in this thread does the OP say whether he's fed or cali spec. This makes a difference...

2000 cali-spec

Same car as me, same code as me.

The precat is between the front exhaust manifold and the y-pipe. You could try to replace the 02 sensor - it's on the precat itself, after the cat material, before the y-pipe but I doubt it will resolve the issue.

You likely need a new precat. I got an aftermarket one made by Eastern Cat from performance peddler.com. Product ID: EAS40387, $190 shipped AFTER maxima.org discount.

Just bumping this thread. I just had the above mentioned pre-cat installed. It's been about 200 miles and still no P0430 code.

You need to hook up a good scanner to see if it is reporting I/M readiness completed.

But given that you have put the new pre-cat in, your P0430 should go away.

I am somewhat surprised that Maxima has rear O2 sensor(s) *before* catalytic converter(s). There is nothing to measure the efficiency of catalytic converter. The sensor(s) check for the health of pre-cat(s). How much pre-cat(s) cost? I know generally OEM cat are quite expensive.

- Vikas

Yes, I'm aware - but considering a drive cycle is less than 200 miles, I believe I'm fine.

It has sensors before and after. The dealer quoted me about $700. I went aftermarket for $180.

Cost me 500 through a private dealer and that wasnt OEM....Shoulda just went to the dealer for peace of mind lol :rolleyes:

Anyway, GL w your prob. I had the same code. 2000 max - fed spec.

Gonna get rid of the other pre cats and their problems when I re do my exhaust.. cant wait

Just out of curiosity, did you have to get new gaskets for either end of the pre-cat or were the old ones reused? I'm ordering one and I'm wondering if I should get new gaskets. My car has 152k miles.

The bottom comes with a crush gasket (ring shaped). As far as the top I went to nissan and they told me it wasn't necessary hence the reason why one didnt come with my aftermarket cat. But it turned out to be like $10 so I ordered it anyway. Its a ring shaped gasket made out of what seems like wire mesh. I mean why not? your already there..might as well do it.

Agreed, get it just in case. The way the cat I bought was designed, it was flush metal to metal with a lip, and there was no gasket needed. I found this out after the fact. I actually have them for sale...the two top ones, if you want them.

I, too, just got the P0430 code this weekend. I have an '01 Maxima with CA emissions and 113K miles. I'm hoping that it's the O2 sensor as its the only one I have not yet replaced so that will be my first shot.

In the event that I do have to replace the pre-cat, just how difficult of a DIY project is it? I'm in New England so I'm sure the bolts will be full of rust.

Any words of wisdom are appreciated!

It's not easy, but doable for someone experienced in (rusted) exhaust. Get ready to have tools such as tap and die, rounded bolt removers, heli-coils and the like on hand. Be very gentle with the bolts, after all you're dealing with exhaust.

Might be worth the few hours of labor a shop charges. The pre-cat itself is not extremely expensive. I have gaskets for sale if you need ;)

Thanks for the input. My O2 sensor is on its way so I'll keep my fingers crossed. Once you mentioned tap and die I know it's more than I can (or want) to handle. I've become good friends with a local indie and will go to him if needed. I'll get in touch with you if I do need the gaskets.