ABS/Traction lights just came on.
 

I just replaced all four brake rotors and pads about a week ago (2007 A3 FWD 2.0T FSI). I started at the passenger rear. I opened the bleeder while I attempted to push the piston back. Nothing happened until I learned I needed the tool to rotate the piston (you know, read directions when all else fails). I did not open the brake bleeder(s) on the remaining three calipers because this forum (I think I read it here) said it wasn't necessary. Yes, it did push some fluid out of the reservoir. Now both (yellow) ABS/Traction lights are on plus the 'Brake' (red) warning light is flashing. I'm going to bleed/change the brake fluid to remove any air I may have introduced and remove any 'crud' that may have been pushed back into the ABS module. My questions are 1.) Was I supposed to open the bleeders to keep from pushing fluid back into the ABS or not?, and, 2.) Do I need to clear the codes before these lights go out assuming I'm successful with my plan? Any help is much appreciated.