Hello peter here I have a peugot 306 2.0 hdi meridian year 2000 w reg?

The abs light has come on and wont go out I have changed the brake discs & pads all round both rear callippers & both rear wheel sensors earth connectons have all been cleaned as also the toothed hub but the light on the dash wont go out I have tried replacing the sensor wiring loom but that didnt turn light off I have had cars computer plugged into on several occasions by 3 different people to try and tell the computer to reset the sensor but the fuault will not clear the abs system is still showing a problem on the right rear wheel sensor any ideas of curing fualt or what might be the problem welcome been quoted price from peugot dealer for abs ecu of � 550.00 approx to be paid in full before ordering and ecu is none returnable dont want to take this route if I can help it