How do you make 2006 Nissan Altima recognize the key?

To make a 2006 Nissan Altima recognize the key, ensure that the key fob's battery is functioning properly. Insert the key into the ignition and turn it to the "On" position without starting the engine, then turn it back to "Off" and remove the key. Repeat this process several times (usually around six times) to reset the system. If the issue persists, you may need to reprogram the key or consult a professional for assistance.