why is ABS/brake/traction light on,brakes work fine,not always on. on 2004 Chevrolet Malibu Maxx

changed disc pads about a month ago while driving hit pot hole
and now the Abs/traction control/and brake light come on and stay on until turn off car when restart its off the will come on when put in reverse some times or when hitting rough spot, the brakes work fine

Have the ABS module scanned for the information for repairs. You can repost the codes.