I have a craftman garage door opener, I also have a built in electronic key paid in my 2004 BMW. I am trying to get it to able to open my garage door with out me using the handheld device that came with the garage door

Do you have the owner's manual that came with your car? It's a case of using the buttons behind the rear view mirror but it's a fairly lengthy procedure. If you're stuck I can type it out but if you have the book, it's in there. The procedure is different if the opener has a rolling code.

Judy hits the nail on the head here. The issue is with your car's owners manual and less to do with the door opener. You will need to follow both manuals to get the car control to open the door. For many of us it can take more than one try because, in essience, you are reprograming 2 small computers and just one misstep will result in total failure.