Alright, I don't understand why a car with 55K would be having any problems with emmissions. So what else could this be(I know there a list of things and I need to get it diagnosed) But a couple of quick questions?

1) This isn't by any chance covered under the 60k powertrain warranty?

2) Is there any type of relay to shut it off (I remember in my girlfriends Integra, there was a button to turn of the "maintnence required" light off (it was so you pay $75 to get your oil changed).

 

If you notice any knock or power loss it might be coil. I had mine go with 50k and I got the code pulled at Autozone. P1320 with P0304 being the coil in cylinder 4.

 

1) There's always a chance, but the odds aren't in your favor. It's probably a bad O2 sensor (you have four of them on your car), and, unfortunately since you're in CA, getting the code pulled by Autozone for free isn't an option (not a problem in the other 49 states... )

2) Nope. You can disconnect the battery cable for an hour or so to reset the light, but it will most likely come back on eventually. You're probably better off taking it in and paying the $80 or so diagnostic fee and have Nissan tell you what's wrong. Or if you want to go a cheaper route, any garage can do the same for less money, but they may not interprete the codes quite the same (some of the "book" descriptions are pretty vague) and you may end up fixing something that isn't broke. Of course you can also purchase and OBD-II code reader. They generally run between $100 and $150.