Make sure there is no grease on the abs speed sensor ring on the outer cv joint of the Drive shaft. in order to check this you have to remove the drive shaft or you could try and cheat by pulling out the speed sensor that is on the steering knuckle and spraying some brake clean or carburetor cleaner in there to get the grease off. another quick check is make sure that your all your tire sizes are the same Example 195/65/R15 195/65/R16 if you have one tire that is a Is a 15 and the rest are 16 that could also cause the problem.
