If you want to do some coding on your bmw or just to check for errors you will need this tools. You can do a lot coding. All you need is obd2 adapter and laptop. You can buy it for aprox 15 eur.
Here is link to Bmw tools. Just install them on your windows xp or windows 7 os.
https://mega.nz/#!kAASwa7I!AJLVnnEBwLgzDPzBeQ4uQo60p1lbU2BsZofE-TBYGmk
Enjoy.