You can hook your engine code reader up to it, it's just like the ecm input. It's push pinned onto the bus/fuse block in front of the drivers side shock tower. You can seach for code meanings here somewhere.
Likely one of your sensors is damaged or out of alignment with the abs hub ring for some reason. I have a 94 sc with the same problem because my drivers side rear half shaft has drifted out of the pumpkin such that the sensor is about an inch away from the abs ring. Shortly after it starts moving the anti-lock light comes on.
Note: Your ABS is deactivated when the anti-lick light is on. Just be aware of that little fact.
I'd start by getting under the car to make sure each sensor is in line with the abs ring.
Cheers
MB