Id appreciate some advice.
I have a 99 with cali spec, and i keep getting a code saying bank 2 catalyst inefficiency. I have all new O2 sensors, so im suspecting the bank 2 precat has gone bad. nissan wants a ton of money for a new one. does anyone have any suggestions? can i find one at a junk yard possibly? is there anyway to trick the car into believing it is normal and not cali spec???

thanks for your help in advance.
-CUSEMAX

unfortunately being in central ny i dont have access to many junk yards so the likelyhood that i can find the part i need at the yard is very slim, and even if i do, the closest one is an hour away.

 

I think it means that the readings from the o2 's before and after the rear converter is too close in voltage. The code means that the reading from the o2 in the front of converter is too close to the reading from the o2 after the converter. So I think ya gonna need a converter. It is the rear bank towards the firewall. But to be sure your gonna have to measure the volatges of both o2's

 

I think he is right... The voltage from the precat O2 to the postcat O2 is much to close so the ECU is thinking there is a problem with the precat converting polutants correctly. If you just replaced the sensors I would recheck the connections and make sure they are screwed down fullyI think he is right... The voltage from the precat O2 to the postcat O2 is much to close so the ECU is thinking there is a problem with the precat converting polutants correctly. If you just replaced the sensors, I would recheck the connections and make sure they are screwed down fully. Though I am sure others will chime in also with advice be sure to check the FAQ's for any useful information on engine codes.

 

Joeeey, I was under the impression that bank 1 was the one towards the firewall, and bank two was the one towards the radiator. My car has 4 O2 sensors becuase it is the cali spec. The way it is set up is that on bank 2 there is one o2 sensor upstream accessible from the engine compartment, and then one that is downstream after the precat. Then the same applies for bank 1, though both are accessible from under the car exclusively. I think you may be on to something about the voltages being to similar. That said it seems like i will have to check it out, and may have to replace that front cat. If i am wrong and bank 2 is towards the firewall, i think the problem may be due to replacing my ypipe with a warpspeed one. The precat on the firewall side was replaced when removing the old pipe. If this creates a problem for my car I dont know what my next move is!
Thanks for your input.
-CUSEMAX

 

CUSEMAX- do you have a y-pipe? what is the number of the code you are getting? I recently had a code 0430 come up, it is for the front back precat (the one not replaced by the cali spec y-pipe) I had to replace that precat. and it was expensive even with my dealer discount $500.

 

The code I am getting is P0430 as well. It says Catalyst Efficiency Below Threshold (Bank 2). It sounds like you agree with me that the Bank 2 is the Front bank, and the precat wasnt replaced with the cali spec y-pipe. What do you recommend? I certainly dont want to spend $500 to fix it!!!!

 

you have to replace it, that is the only way to get the code to go away and get your car running better. i noticed an improvement in gas mileage and power when i fixed it. it is an easy job to fix it, the part is just expensive.

heres a link to some info for you
http://forums.maxima.org/showthread....highlight=0430

 

UPDATE:
I called a local junkyard and they had a 99 maxima there, they woudlnt tell me whether it was cali spec or not, but refused to "service" any exhaust parts. I told him that id come and take it off the car myself etc, and they refused... is there anyway to convince them? what can i do?

 

Bank 1 = right cylinder bank
Bank 2 = left cylinder bank
CUSEMAX Wrote:
UPDATE:
I called a local junkyard and they had a 99 maxima there, they woudlnt tell me whether it was cali spec or not, but refused to "service" any exhaust parts. I told him that id come and take it off the car myself etc, and they refused... is there anyway to convince them? what can i do?
I belive it's a state law that converters can not be sold used. But I'm not sure about that. When you installed you Warpspeed y pipe it removed the front converter. correct? THe reason that I ask is cause I also have a 99 SE w/ Cali emmisions, which I didn't know until I received the y pipe for a fed emmision. I called Dallas (Warpspeed) and he told me my max was Cali. So I'm waiting for a replacement y pipe from them. But when I had it in the air I was loking and it looks as if the y -pipe has the front converter on it as one piece. Or maybe there was a seem under the heat sheild which I didn't remove yet. SO if you removed the converter then thats why there is a code for it. I know they offer a o2 simulator which produces the proper current to kind of trick the ECU. But I got to look into that. Let me know if you had to remove your front converter with your y pipe.

 

02sim.com

..........

 

the front bank pre-cat is not removed when putting on the y pipe. it is bolted to the exhaust manifold, then the y pipe bolts to it. and yes it does have a heat sheild on it

 

with the warpspeed y-pipe, you do not remove the front pre-cat, the pipe they send you does not have the front part, it does repace the rear precat though which is why the o2 sensors are moved around a bit. I cannot beleive its illegal to buy a used cat, whats the big deal??? if it works, it works, they are too expensive. does anyone know if it is something that you can fix??? like can you take the cat apart and remanufacture it? I am not looking to spend 500 bucks to fix it!

 

you cant fix it. it is the element inside it that went bad.

 

Ahhh I know of plenty of junk yards that will sell it to you but you have to go there. They will not tell you over the phone that they will sell it to you. But if you go there and cash in hand you'll get one.

 

its an hour away , but maybe its worth the drive...

 

"Smoke screen" that's what they call it. They do not want to be quoted selling a pre-cat. It happened to me when I went to the muffler workshop and told them if they can remove it. They said it's illegal and they will not do it. They will remove "the pipe" though.

 

thanks guys im gonna take a drive today i think

 

Anyone know the part # of the front precat, the junkyard wouldnt sell me the part used, apparently i looked like i worked for the state (j/k) but they were very professional in saying that they would get fined for selling it to me. They wanted nothing to do with it, i am no good at asking people to the look the other way, so i left very unsatisfied...

 

"i am no good at asking people to the look the other way, so i left very unsatisfied..."
lol
If you were closer to the city I'm sure I could help you out. sorry

 

for the price of that part id drive to the city... my parents live in poughkeepsie, so its not that far to the city... i also have friends in staten island that i visit frequently, so its not a bad trip... if you can find anything please let me know!
thanks
-CUSEMAX

 

for those of you that are cali spec, i have a question.. i ordered o2 sensors in the group deal from automedic(oxygensensors.com) and i think they sent the wrong one.

I ordered 250-24284 this was to replace the downstream sensor for bank 1. This has a black connector on it. The one they sent has a grey connector on it. The problem is that i ordered one 250-24284, and one 250-24286, and they both look like hte same sensor, and the both plug into the downstream bank 2 sensor, but neither fits the connetor for bank 1. should i splice the wires or do u think (Mike?) at automedic would replace the one that was wrong?