I was driving home from work when all the sudden the "service engine" light came on , but the car was running fine and continues to run fine..Any information or ideas would help before I bring it into the dealer....

 

Take it to Autozone - they can read the code for free, that way when you bring it into the dealer you know that they are not bs-ing you

 

might be an ecu update i went in the same thing happemed to me and that is what it was

 

I had this happen on my 2002, drove it all the way home from Pa like that. Autozone said it was the O2 sensor. When I took it to Nissan they had to do a computer upgrade along with the O2 sensor...apparently, the code on some 2002's are running rich and fouling the sensor. They would not let me leave with just the O2 (they had problems downloading the upgrade) so they scheduled me to come back and get them both done.