OziRds

Hi. When I bought my 2000 gs300, the guy selling it to me said the "VSC OFF" light was on. When I checked the codes it said Front RH speed sensor circuit. I asked my teacher about it and he said to start off by replacing the sensor. Any ways I bought a 20$ sensor from eBay and it worked... sort of. when I was testing it I noticed my brake pedal acted funny when coming to a stop or slowing down below 10mph. My friend hooked up his scanner and we could see that the sensor did not give any data below 7-10 mph and when I braked and slowed down to 7-10mph it would record 0mph and my ABS would kick on. So can anyone tell me where to start or what to look for? could it be electrical or just bad luck with a cheap sensor?