Actron 8590 ABS Scan Question

Does anyone out there have and Actron 8590 scanner and know how to get it to scan ABS codes. The website says that ABS is fully supported on the 1999-2008 Grand Prix, but I cant figure out how to make it scan for ABS codes. I did get all of the other codes, 4 total, but no ABS. I do have ABS and TRAC lights on and was hoping to figure out what the problem was. Any ideas there??