Had the the same problem, had to read codes from under bonnet, mine was abs sensor front right got a second hand one put it in, cancelled fault and all ok now, not sure was mine the actual sensor or the plug where sensor plugs in before i got sorted lights woulld come on some times not on all the time, think mine could have been a brake in a wire or sensor,, watch out ya have no traction cntrl workin when the lights are flashin