Hello, I purchased a 2008 Infiniti G35s 6MT sedan with 56k miles few months ago. The car came with test pipes, and since in NJ you can't pass inspection without them, the previous owner gave me the stock cats and o2 sensors. Drove the car around for a month or so, and the code P1148 came on, searched and it regarded air fuel ratio. I decided to put the stock cats back on so I can pass inspection and went to Meineke. After driving about 50 miles or so to allow the car to recognize the cats, I came back to see if any codes would come up, and everything was supported, however code P2A00 came up and was pending. So I know it is an o2 sensor problem, but my question is which o2 sensor needs replacing. I understand there are 4, 2 upstream and 2 downstream. The 2 downstream senors were the ones that the previous owner gave me, and he had taken them off to put his test pipes on, so the sensors and cats sat around for some time. So I'm guessing because of this, the 2 downstream sensors have gone bad and need replacing? Any input would help, I've just been going everywhere trying to find quotes to fix this and more information would help. thanks

 

That's an A/F sensor code (upstream). I'd check for intake leaks or how about the gasket between the CAT and exhaust manifold. If you do need O2 sensors I have a used set of 4 OEM I bought, I could part with for like 50 bucks.

Try swapping the two front sensors they are interchangeable and see if code swaps over, I don't think the rears are though. At least on my car they weren't.

 

any one else with some input? it would be appreciated!

 

bump!

 

bump! any info?

 

bump!

 

I had an intake leak with this code. I advise you to check again.

 

thanks guys. trying to get more input, appreciate it.

 

Bank 1, sensor 1 which is right front sensor

http://nissanhelp.com/diy/obd_codes/p2a00_infiniti.html


I found this

 

Hey Haz, alright if you crawl up under the car there is a U shaped bracket that bolts to the bottom of the transmission and connects to both cats. Check each cat where this bracket bolts up. I would almost be 99% positive that the weld on the cat is broken and is leaking exhaust. I have seen hundreds of these and they have always been on V36 models. It is very common and the only fix is to replace the cat.or have someone weld the crack back up. The sensor more than likely isn't damaged at all. Hope this helps brother.