ABS scanners are usually of the high end or very expensive category. The Snap On MT-2500 has ABS capability as do the Tech II scan tool GM dealers use. The major problem is these are expensive $$$ and used primarily by the Pros. The Tech II is actually the best scan tool to use because it will properly retrieve and display GM Mark VI ABS codes with proper translation. So you may consider just taking it to the GM dealer for ABS diagnostics only. Another company called SPX/OTC makes lower cost ABS/Airbag scanners but they are over $1K in cost.
Click here
With ABS capable scanners tests are run while the car is moving to check wheel sensor speed output and also while not running ignition to on just like a regular odb-ii scanner to check other ABS components like the modulator, motor pack, solenoids and EBTCM module.
You might just consider making a post at Grand Am or N Body Problem Diagnosis and have your ABS issue discussed.
And welcome to AF.