ABS light on, Motor on ABS system run after key OFF

The small "booster" motor on the ABS system continues to run even after the engine is off. It ran all night last night and drained my battery. In my repair manual it says to check the fuses, and get the trouble code read. My problem is now that the battery is dead I am stuck with having it towed somewhere and I am afraid that once I get it to a shop I will be stuck there and have to pay for whatever repairs they want to impose upon me. I would like to get an idea of what the problem could be before walking into a shop. Thank you to whomever takes the time to help my with the problem.