2001 Peugeot 307 knocking when bracking at slow speed

hi there when braking and get to a slow speed ie 10 mph or below there is knockin that comes from ns front wheel as if its the caliper is hittin the wheel as it turns, i have replaced ; disks+pads, brake caliper, abs sensor and the abs pump but still persists. the only way to stop it is to un plug the abs sensor but the abs light comes on the dash so it will not pass the mot in 2 months.
could it be a fault with the ecu please help many thx kev