2002 Nissan Maxima car start but turns off

Was the replacement key made by the dealer and has the correctly programmed chip? If not, that's exactly the symptom I got on my car. I made a duplicate key of my original, and it worked fine as long as the original was attached to same keychain. But if I just started with just the duplicate key it wont stay running. Now I keep the dup in my wallet in the case I locked myself out with engine still running. I can then open the door with the key and get back in.