Ok I own a 2003 g35 sedan 101k on it and the check engine light has been on for about awhile and today I went to autozone and had the codes pulled. It pulled 5 codes and I find it hard to believe that all of them went bad. The codes where
P0031 bank1 sensor 1 heater circuit low
P0051 bank1 sensor 2 heater circuit low
P0037 bank2 sensor 1 heater circuit low
P0057 bank2 sensor 2 heater circuit low
P1148 closed loop control bank 1 sensor 1

Now Im thinking maybe the bank 1 sensor 1 maybe causeing the others to go off. Im not really sure At first I was damn it I gotta replace all four but then I was thinking how can all four go bad at once. Help me out g35driver so I dont gotta replace all of em.

 

err...didnt read the whole thing.

Its possible you have just one. I would start by replacing both of the foreward sensors. the others aren't as important

 

Try to have them clear the codes and see if one pops up before the others. Just a thought.