2001 Pontiac Grand Am Dash board lights coming on?

Heres a fun one. Almost every time I drive, I can drive for a few minutes, and everything is normal, but most of the time, for no particular reason, the car goes "ding ding ding" and the ABS light, the TRAC OFF light and the SERVICE ENGINE SOON light all come at once. They stay on for the remainder of the trip and then when I turn the car off, they go away. But, the next time I drive, the same thing happens. Its really annoying and I dont know what might be loose or poorly grounded. Or if its something more serious. SOmetimes I think it comes on because I hit a little bump in the road, and it came on once when I was going around a tight corner, but I think I hit a little bump then too. Its very frustrating. If something is loose, where might it be and how can I fix it? I cant really afford to take it to a shop.