2002 Chevy Impala Service Traction Control

Just like what was posted by Chevyone: traction control & abs come on intermitently. Service traction system message will come on @ times. Traction control seems to activate when you first start the vehicle and go from reverse to drive then the abs seems to activate more often when braking at low speeds or if a bump is hit. This started about a month or so after pads & rotors were replace. Wondering if this could be a wire or sensor problem?

I thought at first the problem was because I wasn't allowing enough time between reverse, coming to a complete stop, and the moving into park. But after allowing the vehicle to come to a complete stop, counting to 5 and then putting into drive and the traction control becoming active.

Any help that can be give would be greatly appreciated.