Can you try the scanner in another car to confirm the scanner operation? then lets check the ALDL fuse #30 in the under hood fuse panel. here is a guide and the wiring diagrams so you can see how the system works and the fuse location:
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.