If you go to the service manual that's online as part of this site
http://www.thenissanpath.com/viewtopic.php?t=2 there's a procedure on page 37-38 of the restraints section. You can diagnose the airbag system by counting the flash patterns.
Mine did this awhile back and I was able to diagnose as a front crash sensor. When I googled the part I found out it was part of a recall so my dealer replaced it, no charge of course.