Code 0430 popped up about a year and a half ago. It's something to do with catalytic below threshold or oxy sensor. The fix last time was to reflash the computer. It was under the emmision warranty then. Now it has expired.

Does anyone know why this code is thrown again? Do I need to reflash again? Or is it the oxy sensor this time? Or is the cat actually bad?

It has 93K miles now.

 

I have the same amount of miles on my 2000 and I just went through a situation with P0430 along with a couple of other codes (P0139, P0159) that are covered in TSB NTB02-051a where the TSB says to change the both rear o2 sensors and and flash the ECM with updated programming.

NTB02-051a does not mention P0430, however that code went away along with the other codes when it was applied to my car.

There is a separate TSB that covers P0420, which says to just flash the ECM without changing the sensors.

I would say if your rear sensors were never replaced, perhaps they should be and go with a Nissan part rather than Bosch or some other company

 

I will try to change out the rear sensors, they are original. Hopefully, this will stop the code from comming back without reflashing. It returns much quick now then when it first started. It used to take a couple days to return after a reset. Now it returns the same day. This could point to a degrading sensor, right?

Thanks!

 

It probably is, but unfortunately it could also point to a failing cat. That was the warning I got from Nissan and another shop.

 

chances are your cat is bad,all maxima's have o2 and cat problems. due to same problem i had my pre cats replaced with cattman y pipe for better performance and light has yet to come back. i have old o2's still in car. o2's can be checked to see if there performing correctly. good luck

 

Living this nightmare as well. I have already changed out the o2 sensors (DaveB plug). The 0430 came out about 6 weeks ago and went away by itself after 10-20 restarts. Came on about two weeks ago and went out shortly thereafter (no battery disconnects either time). I am going through emissions next week and will let everyone know how I do (Pennsylvania emisions - hose taking readings at the tail pipe). I have been researching this here on the org, and am at the point that if I fail emissions, I will be buying a precat. Getting estimates ($250) used, to about ($700) new. The sensors are easy to replace, but a friggen bit$h to get off. There is a link on the org (.....owensfamily....) that has the TSB and extremely helpful.

2000 Max Se - Black
149K - stock as can be
Cali spec

 

I have this exact same issue...

Light first came on in december during drive to KY. Got it cleared and didnt come back until mid jan. I have not bothered to go get it cleared yet...

In jacksonville, FL now and no emissions testing so not really bothered LOL...

one of these days i'm just going to pop the dash and remove the SES led

 

I did some research and found that the following problems could cause the code assuming o2 sensors are okay:

Three-way catalyst (Manifold)
Exhaust tube leaks ( before three-way cat)
Intake air leaks
Injectors (misfire)
Injector leaks (misfire)
Spark plug (misfire)
Improper ignition timing

 

I spoke with dave B yesterday... his take was if it is only a P0430 almost 100% of the time it is the cat.

I was searching online last night and found several generic Cats for under $200.

 

My SES has been coming and going for five months now. I figured that I would have to replace the cat, but I reset the SES (pulled battery cable) and took the care in for PA inspection/emmisions. Passed! Am experiencing no loss in gas mileage since this problem started (20 MPG). Good luck to everyone else.

 

P0430 is for FRONT PRE-CAT...NOT THE REAR PRE-CAT and NOT THE MAIN CAT.

I went through this whole scenario with P0430...I had to replace my front pre-cat to eliminate the SES light.

 

yeah this is what my mechanic told me today he already replaced my main cat and the light went away (probably reset) and now it's come back.