The steering position sensor is the most commong cause for receiving that message. There is also the lateral accelerometer behind the back seat, but you weren't near either from what you've said. You may want to check each of the wheel speed sensors at each wheel to see if you knocked loose, or damaged any connections or wires. I'd expect an ABS light to come on with that, however.
I agree with steering position sensor, they seem to be sensitive, mine goes off all the time now.Isnt it just a plastic disclike piece.Have you had the intermediate shaft clunk, I am wondering if all the clunking I had before I fixed it disturbed the position sensor.