2002 Other Mazda Models ABS light is on

Hi guys, i have a 02 mazda millenia 2.5 V6. My problem on my car is when my car hit 85 miles per hour the ABS turns on but my brakes are working fine in all that..then the next day the ABS indecator will disappear..But before that ABS came on i replaced my cv joint it was my rf axle..then a week later i was in the highway i reach up to 85 miles per hour the ABS light indecator came out and that was the first time i saw it..let me know what you guys think is the problem...thanx..you guys rock!!!