my service engine light is on, can it be a oil change?

hello, i drive a 2009 nissan 370z (base model- manual) and usually when i'm at a complete stop and i'm in neutral my rpms stay right under 1000rpms but this morning my "service engine soon" light came on and i noticed my rpms's stay above 1000 rpms... would you happen to know why my rpms are like that? and maybe why my light came on? maybe a oil change?