I was driving to class and the SES light came on, i called my mechanic and he asked if i changed the oil recently (did it 400 miles ago) , filled up gas last night. After he asked i tightened up my gas cap again. An hour passes by after class and i drive it for 10 mins and it goes off. What could of made it go off.

I have 60xxx on my G , changed Rear Diff, Flushed coolant, all fluids, and transmission at 55k.

 

bumpoloopo

 

OBD 2 check

 

Some auto parts stores do free code checks.

 

Try removing the negative side of your battery over night that should clear up any issues. If this happens again drop by your local Nissan dealership and have them clear it up for you, likely nothing serious and the cost w/b minimal....
Gary