My 1991 Buick Park Avenue Ultra's ABS systerm dash light is staying on while driving. What does this mean?

Your OBD has detected a fault in your Anti Lock Brakes. You can still drive the car, but will not have ABS, but I am not suggesting you ignore it, it needs to be fixed.

the sensor just is not being read by the computer...on some cars with "traction control" will start to feather the brakes on...we don't want that...inspect your electrical connections to the sensor(s), see if we cannot figure out why the computer isn't seeing the signals. Perhaps it is time for a NEW battery, would be an opportunity to wirebrush and refresh the cable to ground connection, the ECU would not have "brown power" and could see the signals clearly....couldn't hurt~