I have been told this problem is so common on the Micra and its about time they soughted it out, Other than the fact that the Nissan dealers will can charge lots of money to put it wright (easy money for them!) Here is the simple answer turn the ignition on wait until the warning light starts to flash and wait about five seconds and turn it off, do this three times, the next time you turn the key the warning light will flash slowly, it is now in diagnostic mode, turn off the ignition leave a couple seconds turn on the ignition and the problem should have been solved. I have been told this problem is caused by dodgy electrical connections under the front seats which only have to be disconnected for milliseconds to activate the warning light i.e a drinks can or a can of deicer rolling around on the floor and knocks the connection (this in my case!).Hope this helps you.
John Wakefield
February 2011