How to get vehicle out of anti theft mode

I'm assuming you disconnected the battery to do the fuel pump repair. That was the correct thing to do. But if the security system was armed when the battery was disconnected the security system probably locked down the vehicle. Try closing all the doors then lock the vehicle with the key fob. Then unlock the vehicle with the key fob. Once the vehicle recognizes the key fob by doing that you should be ok. Hope that helps! Jim