2002 Nissan Sentra Owner's Manual - Page 75

KEYS A key number plate is supplied with your keys. Record the key number and keep it in a safe place (such as your wallet), not in the vehicle. If you lose your keys, see an authorized NISSAN dealer for duplicates by using the key number. NISSAN does not record key numbers so it is very important to keep track of your key number plate. A key number is only necessary when you have lost all keys and do not have one to duplicate from. If you still have a key, your authorized NISSAN dealer can duplicate it. in your vehicle by an authorized NISSAN dealer. As many as 5 NVIS keys can be used with one vehicle. You should bring all NVIS keys that you have to your authorized NISSAN dealer for registration. This is because the registration process will erase the memory of all key codes previously registered into the Nissan Vehicle Immobilizer System. After the registration process, these components will only recognize keys coded into the Nissan Vehicle Immobilizer System (NVIS) during registration. Any key that is not given to your dealer at the time of registration will no longer be able to start your vehicle. NISSAN VEHICLE IMMOBILIZER SYSTEM (NVIS) KEYS (if so equipped) You can only start your vehicle using the keys that are supplied by your NISSAN dealer. Each key has a transponder chip in the key head that is electronically registered to your vehicle's NVIS. These keys can be used for all of the key locks on your vehicle. Never leave these keys in the vehicle. New or duplicate keys can only be obtained from your NISSAN dealer and must be registered to the Nissan Vehicle Immobilizer System (NVIS) components WPD0102 3-2 Pre-driving checks and adjustments