The anti-theft system works like this:
If you use the key fob or power lock to lock it, then use the key to unlock it, the anti-theft goes off because it thinks it is being broken into. It does this because it is very easy to unlock the car with a slim jim (I know because I've done it a couple times). So, it senses the lock moving, but can't tell if it is a key or something else, so it goes off anyway. Kinda nice IMO. But... On the other hand, if you lock it with the key, it does not activate the anti-theft when the key is used again.
Hope this is understandable.
If you use the key fob or power lock to lock it, then use the key to unlock it, the anti-theft goes off because it thinks it is being broken into. It does this because it is very easy to unlock the car with a slim jim (I know because I've done it a couple times). So, it senses the lock moving, but can't tell if it is a key or something else, so it goes off anyway. Kinda nice IMO. But... On the other hand, if you lock it with the key, it does not activate the anti-theft when the key is used again.
Hope this is understandable.