See the last paragraph of the excerpt in post #2. Without a proper scan tool to give you direction, all you can do is poke around and guess. I'd suggest paying the dealer to perform the scan to prevent wasting more money on unneeded parts (or just remove the fuse and disable the system).

Here's a new link to the schematic since the old one above is broken: http://www.mediafire.com/?1hx3kmlcxdn

Steve