well you should first find out if you need one or both front ABS SENSORS (save some money). best way to to determine which one is bad is to check resistance in abs sensor (sensor side-two wire terminal). what it comes down to is if you have resistance sensor is good and if you dont have resistance sensor is bad. I think spec is 1100-1800 ohms or close, but again if sensor shows resistance, sensor is good.
hoppe this helps