Ok so I'm making this thread because I already searched and the one thread thats 6 pages long is inconclusive and with other ppl throwing in their own problems makes it even more difficult..

I have a 2006 350z which threw me the code which is shown in the title

P2A03
Oxygen Sensor Circuit Range/Performance Bank 2 Sensor 1

I am running Strupp Headers, with Kinetix Test Pipe, and Greddy Evo II Exhaust.
The car DOES HAVE defoulers that are installed on the O2 sensors that go on the TEST PIPE not on the HEADERS!!!! (Theres a total of 4 sensors from what I saw when i got under the car)

My first question is this: What or which is Bank 1/Bank 2 (if there is any), and what or which is Sensor 1/Sensor 2 (if there is any).

Second question: I read in that 6 page thread one of the members removed the defoulers and it fixed it for him apparently, so I went ahead and did the same and REMOVED THE DEFOULERS. (in my case it didnt work)

another note, on the drivers side header/test-pipe setup, I have an exhaust leak between the Greddy and the test pipe.

On the passenger side of the header/test-pipe setup I have an exhaust leak between the header and the test-pipe.

I personally think that an exhaust leak past the o2 sensors wouldnt cause a SES to come on. But I dont know like I mentioned earlier which is bank 1 or 2 /sensor 1 or 2..
I am considering replacing all exhaust gaskets (header to test-pipe/test-pipe to exhaust)
Any input would be great...

Thank you

 

bank 1 is passenger side
bank 2 is drivers side

sensor 1 is the one by the header
sensor 2 is the one after the cat/test pipe

exhaust leaks can throw all sorts of codes. until you fix that, you will have no idea whats really wrong

 

Like str8dum1 said:

Bank #1 - same side as cylinder #1

Sensors are numbered from the motor back - #1 closest to the motor

 

So according to the code, I probably have a crack on the header on the drivers side, because sensor 1 is the one on the actual header and all gaskets are behind so regardless of a leak by the gaskets it wont matter since its passed that sensor thats "bad".

correct?

 

Sensor is not bad, its doing its job seeing the leak in the exhaust. Front sensor ( #1) O2 tells ECM engines AF ratio and ECM decides what fuel trim to use next, rear O2 tells ECM whether Cat is working. ECM is expecting different 02 readings at each sensor and turns CEL when O2 is out of range for either one.

 

Welcome to the club. If there is an exhaust leak somewhere that pulls vacuum or expels air to/from the atmosphere, your sensors are going to give you false lean/rich conditions. I'd be less concerned with where the leak is and more concerned with making sure there are no leaks, period.

Good luck getting this resolved. I have not found a solution yet, so I disabled the codes with UpRev. Doesn't seem to really affect performance.

 

Exhaust leaks can be a PITA to hunt down, but they're not the worst thing to troubleshoot. It may or may not be in the immediate vicinity of the 1st sensor. If the leak is bad enough, it'll cause issues in the whole exhaust system. Have you tested the sensor to see what voltage you're seeing?

 

first off thank for all your help guys!!I appreciate it

Thank you that does make things much more clear.

Ok but now isnt the exhaust flow unidirectional? and if thats true and my sensor on my drivers side header is bad, how is it that a leak behind that (testpipe, exhaust, etc.) would cause it to throw a light if its already passed the sensor?
Im just asking not correcting lol.

Thanks!!It seems as its a b***h to get this fixed from what ive read in other threads. But I like things to be functioning 100%. If I manage to resolve Ill provide you some input.

Correct, On the side where my sensor is causing to throw the code, there is an exhaust leak between the TESTPIPE AND CATBACK, which at that point has passed both sensors? Also theres an exhaust leak between the test pipe and header on the PASSENGER side. but according to the code theres nothing wrong on that side. Its like I was asking Neimad.

And no, How do i test the sensor? and special tool? what to look for?

 

I'm a little hungover, but I'll give it a shot. Sensor senses Oxygen. Sure it might be leaking behind the sensor but in between every firing of the cylinder atmospheric pressure is slamming O2 back through the now not properly sealed exhaust. This causes an unusual O2 reading at sensor. ECM is trying to keep things clean for the environment, main reason check engine light is there. Light specifically means ECM can no longer guarantee operating within 1.5 times the max allowable EPA/CARB emissions. Catalytic converter requires very precise switches in AF ratio to burn off excess emissions, ECM uses O2 B1S1 and O2BS1 to see whats coming out of the engine and then sends the opposite next, if it sees a reading next that doesn't make sense with what it sent through it sets a code. If it sees too much O2 at either bank S2 it thinks the cat isnt working.

If that doesn't work I know a few websites.

 

Also, don't test sensor until fixing leak. Think of the sensors as exhaust leak detectors. Because leak=O2 and thats what they look for.

 

LMAO pretty good explanation haha.. ok sounds good I will go ahead and change out all 4 gaskets (header/testpipe x 2 and testpipe/catback x 2).