Are you saying the ridges on the hub have rusted a lot? I think that might be unrepairable if they are too far gone. The sensor relies on sharp ridges AFAIK. As said previously, the computer doesn't care about the RMS voltage. It just looks at each pulse and decides if it is "high enough". It is possible that by moving the sensor closer you could "fix" a missing pulse that was barely high enough. But I would guess that if the ridges/grooves on the hub are badly rusted you may need a new hub.

Look at the last few posts of this thread (search comes to the rescue again...)

http://www.peachparts.com/shopforum/showthread.php?t=233453&highlight=rust+hub+abs

This person had a rusted hub.

I searched on "rust hub abs"

Good luck

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra