Audi Repair: abs and brake light flashing on, ujoint, hydralic

Question
I have just replace the ujoint on the drivers axel and these light came on.  Fluid was a little low in the master cylinder and added regular brake fluid and the hydralic was a little low and added hydralic fluid.  Light did not go off.  May have disconected wire for a short period during axel repair.  Any help?

Answer
hello
just make sure that your sensor is pushed in , sometimes they like to get loose (expecially the one where axle was working on). I hope the new joint came with ABS ring.
If that is OK, you will have to scan for faults
good luck                      pltech