flash on your instrument panel with the check engine light (CEL). To see where this light is located just put your key in the ignition and turn it to the start position where all the dash lights go on and look for the CEL. When you activate the ECU to be in the check the codes mode the CEL will flach as I noted in the post. You can also take the car to Auto Zone and they will do a free code check. If you take it to Nissan they will charge you.
Best to learn how to DIY for the codes and other things or else pay the $$$$$$.