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smoked cat probably, does ur car smell like rotten eggs. the sensor giving the code is b2s2 since it is the one that determines catalyst effeciency.
 

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could be a faulty upstream or down stream O2 or a bad catalyst OR an exhaust leak. All of which can cause the failure described. BTW What are you doing to your car lol. Every other day I see you posting some strange problem on here lol
 

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Discussion Starter #4
lol well my lifstyle has changed i used to wash my car every other day ( no joke) leather condition the seats every four days. i would even remove my rims just to clean the insides.also i was buying little mods hear and there. but i have been working so much latley 12 hour days + weekends there is no time to do that. also its 20 degrees where i am so that makes it hard to. but i think my car is mad at me couse i have been showing little to no attention.

but in any event back to the issue. the cats do not smell at all. there are 3 cats and 4 02 sensors in the is300 correct? if its the 3rd cat on the b pipe . it doesnt bother me couse i would liek to order the aftermarket b pipe anyway . and if i have to i would put a new sensor in that pipe aswell while its out. but what your saying is that code can mean any cat and any 02 sensor?
 

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I'm saying it needs to be properly diagnosed. I would need to see the readout from the O2s to determine whats acting up. Throwing downstream O2 at it probably wouldnt hurt though
 

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way more, the change rate may be too slow, the heater could be faulty,it could be a goodreading with a leak, but all in all if your gonna get a y pipe, who cares, its gonna throw codes then anyways so you need to get an o2 simulator. tom is right thatchanging the o2 isnt a bad idea, however i am not the type of person to change parts and hope that works, i would rather diagnose it right the first time and know it was the right fix. you can add propane through the intake and watch the switch rate of the primary o2 sensors. then you should see a rich mixture with a lean command when the secondary confirms that you are running rich because of the propane. if the secondary goes way rich then the cat isnt working and there is the problem, but in the state of california law requires that for a tech to diagnose a cat failure it must fail 2 out of three tests first then they can recommend a new cat. hope that helps
 

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Discussion Starter #8
cell for p0430

so my cell came on a few months ago for p0430 (Catalyst System Efficiency Below Threshold Bank 2 ) 2 days later it went off. 3 months later wich was yesterday it came on. so i scanned it and it said the same thing (Catalyst System Efficiency Below Threshold Bank 2 ) i erased the code and it has not come back. my buddy tells me he thinks its one of the main cats built into the exhuast manifold.i never get a rotten egg smell at all . even if i were to floor it many times in a row the exhuast never smells at all.i was hoping it was an 02 sensor. any input?
 

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po420 / 430 codes will more than likely always be catalyst failures. There are specific codes thrown for the b1s2 / b2s2 failures / heater failures.

Get yourself an o2 simulator - $50 bux and the headache is gone.

Atleast once a week i get a customer car that pulls a 420/430 code with no smells from the cat converters. Hope that helps
 

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Discussion Starter #12
i erased the code and its back now a month later. there definitly is no exhuast leak, so this has to be the cat or sendor you guys feel? there isnt mods to my car that it should throw it due to tuning issues.amyone have any input?also thank you for the replies so far
 

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You have to check O2 sensor bank 1&2 sensor 1. If no good>replace it, if it's good, check O2 sensor bank 1&2 sensor 2. If no good> replace it, if it's good (worst case) then you have issues with your front & rear 3 way cat.
 

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Yet another owner with the P0430 b2 problem......damn it

can I simply replace the sensors?

If so, can anyone direct me the replacement number for NGK ??

Thanks in advance
 
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