What year isit? The later ones all have remote locking (I think). If you hit the lock button inside the door and later just unlock with key, this is normal. I'm not sure if you can avoid the alarm by manually locking the door with the little lever at the inside handle... Meaning to lock all the doors while engine is still running, unlock the drivers door and then on exiting lock the drivers door manually. This might avoid activating the built in alarm. My guess is that the alarm WAS disabled before and the loss of power re-set it to "normal" i.e. functioning.