Ok,
I just purchased a used 08 Infiniti G37S with 18K miles and after driving it for a few days I got an "SES" light pop up. I have an OBDII Code scanner and ran a quick check and it provided me with an P2A03 "o2 bank 2 sensor 1" code. The car came with a stillen cat back exhaust & stillen intakes. The previous owner also gave me a COBB tuning ECU. He also told me that he previously had straight pipes on the car. I have tried clearing the code several times and the light comes back on after 2 days.

Does anyone know if I just need to replace the o2 sensor or do I need to do a A/F ratio learned value clear on the car? Or do I need to play with the COBB Tuning ECU to get the A/F ratio correct? I just got the car and don't know anything about the COBB ECU.

Any help would be appreciated.

Thanks,
Dan

 

The previous owner has confirmed that he had staight pipes on the car and never switched back the stage 2 tune when he reinstalled the cats. This might have something todo with the SES reading? I am now curious if I should remove the tune all together.

Does anyone have a cat back exhause and intakes installed without at tune?

Thanks,
Dan

 

Try removing the tune.

I would also check the o2 sensor under the driver's side pipe to be sure it's tight and/or not dead.

When I had my HFCs installed, I threw that code a few days later. My now ex-mechanic didn't tighten the o2 sensor.

 

If my O2 sensor is bad where can I find a cheap replacement The dealer wants $300-$400 for one.

 

I'd check Amazon.com.