I have a 2001 nissan maxima. P0430 code below threshold bank 2. But it passes ca smog. Want to know if its still the catalytic converter front forward or o2 sensor or what it might be. I just bought it and I don't know when the last maintenance was done on it. The radiator is cracked but not overheating could it be the intake manifold throwing this code. There are no symptoms other than the code.

 

No way your car can pass CA smog with this code. Trust me - I just replaced my pre-cats, and didn't even have the code, just "monitor not complete". And yes, I also live in California (Bay area).
To answer your question: P0430/P0420 indicates that either your pre-cat or your rear O2 sensor (or both) is/are bad. More often than not, it's the pre-cat. At this time/age, the pre-cats on our cars are worn out and need to be replaced.

BTW, can you change the title of this thread to better reflect its content ("2001 maxima" is a lousy title when searching). Thanks!

 

Couldn't agree more. I changed the thread title to something more meaningful. Will help those that use the search function.

 

I had the P0430 code for a couple of years here in NY before I donated my 2000, was pretty sure it was the pre cats. The last year I couldn't get the code off.
It was just too much considering the rear wheel well rust and the swiss cheese lower rad support - forget the tree that crushed the roof.
Miss her though.

 

just put a defouler on it and be done with it

 

I just did an on board test with one scanner and it said my cats are ok. But downstream o2 stays between .26 and .29.

 

Well you can replace the O2s now and then replace the precat next week.... Or you can just go ahead and replace the precat now.

To diagnose you'll need to drive the car while monitoring downstream o2 response and know what to look for.

 

That will NOT do in California!
I took my inspection about a month ago; it consisted of the following steps:

• Connecting an ODBC connector to the ECU, and querying the internal status of all monitors plus who knows what else (even the inspector doesn't know, the results go directly to Sacramento). All this done with the car running.
• Under-the-hood inspection of XYZ (not sure what exactly, took about 3 minutes).
• Up-front, under the car inspection, using a mirror on a stick (my guess is: inspected O2 sensor for possible re-wiring, etc.).
• Back/rear, under the car inspection, again using a mirror on a stick (my guess, inspected the Evap. cannister)
• One more thing, can't remember the details. At any rate, total of 5 items.

I knew all this beforehand, and I knew that both my B1 and my B2 cat monitors were NOT complete (low efficiency, down to 35-50%).. So I replaced both pre-cats with Eastern/AP pre-cats from Rockauto, completed the monitors, and took & passed the inspection. Total cost about $800 ($520 parts + $270 labor), plus the cost of smog inspection.
Apparently, these replacements parts are made to last about three years. So I have my fingers crossed that they work through my next inspection in Nov of 2021.

 

I did more on board diagnostic tests and the only failed test was the ho2s Id 1. A heated o2 sensor

 

Go somewhere else.

 

+1 , using a mirror lol, this ain't the dentist =)

 

After I ran all the tests I changed the o2 sensor upstream bank 2 erased the code and 10 days later still no code.

 

great to hear it was as simple as a sensor

 

I have the same code on my 02 GLE and it's telling me the same 02 sensor is causing it. How hard was it to replace yourself? I'm not particularly handy with cars but I can follow some instructions haha.

I'm in CA and need to pass smog, otherwise I think the car is toast and I need to get rid of it. I'm thinking it might be hard to sell a car that has no tags with a check engine light so I'm hoping there is a cost effective solution.

Thanks!

 

i am not a super in depth mechanic ,and i was able to replace both upstream O2 sensors, you need an adjustable wrench and some skills and patience at maneuvering your hands and arms to get inside the nooks and crannies, take a look at this thread it has a diagram where all 4 sensors are located. the two upstreams are bank 1 sensor 1 , and bank 2 sensor 1

https://maxima.org/forums/5th-genera...on-fouler.html

 

had a P0420 on my 2001 i30t did what Scotty Kilmer recommended, bit less than half tank of gas and put a gallon of lacquer thinner in the tank, erase the code, run the car on the highway until you run out of gas, problem solved, I repeated a year later just in case but code never came back after the initial "cleaning".

 

sounds like some backyard hill billy fix lol. laquer thinner in your gas tank? id rather fix it properly.

 

i tend not to argue with results

you want to put more $ into one repair than the car is worth, go for it

 

Yeah lacquer thinner sounds crazy haha. But I'm pretty desperate so maybe? Nah, I think the craziest I will get is Cataclean. I'll let y'all know how that works out.

 

i guess a pair of O2 sensors in canada costs a lot.

 

often the o2 sensors are not the problem, the cats are, and yes everything here is crazy expensive, i never buy local, only on rockauto.com and ship it