2010 Mazda3 2.5L; ABS and Traction Control warning lights on. Help

I have a 2010 Mazda 3, 6-speed manual, 2.5 liter. The ABS, traction control and brake lights are all illuminating--C0002, C0082, C0020 and D0415. Trying to avoid an expensive repair--just wondering if this might be caused by a loose connection or a wire harness (friend's idea) that needs to be replaced or cleaned. Any ideas??