I had to find mine after I got the X. The dealer wanted some huge amount of $$ to plug in thier scanner and read it. It is on the C pillar. Just pull the weather stripping back and release the top trim piece. It's on a little computer module back there.(on a sticker) I had the link above bookmarked, but it doens't seem to work.(it used to) If you do a quick search on google you'll save a bunch of $$.