If your dealer used a Tech II to scan it, they should be able to be more specific than "electrical problem." Problem could be abs module (faulty from factory, requires $150 rebuild), either of the other two wheel bearings, or any of the wiring in between.
I'd say you can rule out the abs module if hitting bumps is the culprit. Wire short or bad sensor is my guess, but a Tech II should give you a better idea.