Well it could be that you have a hard fault that comes back just as soon as you erase it or it could be that you have not driven it above 20 mph to get it to do it's self test and extinguish the light. The early model cars were such that when you put the ABS into diagnostic mode it would not turn the light out until you read all of the codes twice and then drove it at over 20 mph to get it to pulse the pump once and then clear the light. Also it is a 5 second interval and believe it or not every now and then I get a control unit that just absolutely will not reset unless I stand there and watch the second hand on the shop clock and do it EXACTLY by the numbers, 5 seconds and not 8.

Mark