Ive got the same fault on my saff cossie. Since ive changed the osf hub n hub carrier my abs has been like this ever since ive checked the resistance on the osf abs sensor,ok ive cleaned all the grease n crap off the abs ring on the driveshaft. Its still the same some people have advised me 2 check the air gap between the sensor n the abs sensor but i will have 2 strip the suspension down n check. If u find out before me let me know.