It will be the ABS module solder joints as Vert said. I fix them for $150, including a modification to prevent the fault repeating - they have a poor design for the environment they are in.
x10000000
I have had heaps of them repaired, $150 is a good price.
They normaly throw either a wheel sensor fault or a hydraulic pump fault, if you're getting charged 500-1000 you're getting robbed!!!
Anything Electronic in Nelson repairs the modules for 120+gst.