Funny thin is this question just came up with my wife on her Maxima about a week ago. You have to clear the system with a code for that system. I called eight different dealers that told me it can't be done without the seven digit code- which you code only find on the "dog tag" that originally came with the car. However at the ninth dealer, the service tech told me that to reset it, you have to take the seven digit code that you should have the "dog tag" for. However. if you don't have the "dog tag", it's posted on the lower rear of the glovebox. Type that code in and it's suppose to make a few beeps; Then type in the code that you want and all is well. I haven't done it yet but I will when I get around to removing the glovebox to get the code. It's easy but I generally don't have the time to do it. Note: If you don't here the beeps after entering the first code, the code was either entered wrong or the keyless entry system isn't working correctly. Good luck.