BMW Data Link Interface Project
Here are some sites I've found helpful:
http://www.hex.co.za/vaginfo/index.html -- This site has an in-depth description of the "conversation" between computer and ECU. It's for
VW's, but the principle is likely the same.
http://www.carlton24v.co.uk/aldl.htm -- Simlar to the above, this site also traces the conversation between tester and ECU, for a Vauxhall with
an earlier version of Motronic.
www.elmelectronics.com -- Producer of the ELM323 chip.
http://www.andywhittaker.com -- Another great site showing several interface designs.
www.wgsoft.de -- WIndows GUI OBD-II interface software for the ELM series of chips.
Please report any dead links you find at the address below.
This site is not affiliated with BMW in any way. As if you couldn't tell.