Grand Am SE 1999 Wheel Hub Assy / ABS problem

My 99 SE 3.4 V6 has a problem with the front brakes. It was scanned 3 times and it was the RF wheell bearing (bad sensor) I thought this was odd to have 3 defect (Precision Brand) wheel hubs but then at a local Tuffy Center they replaced it with a Timken bearing and I still have the same results. The guy then tells me that its possible that when I drive the voltage in the the ECBM is dropping from 14.3 to about 2 volts and thats why the ABS light keeps coming on. Also when it starts from a cold start I back out.I keep getting the LOW TRACTION light then the right side makes a scraping noise then the TRAC OFF and ABS lights appear for th rest of my trip. HELP!