The Anti-Lock, Trac off and Service Engine Soon (left one) come on after I have started the car and the car has gone from a few feet to a mile or two (sometimes more). The cruise control works fine and no brake lights are out. The computer says it is a left front ABS sensor. It costs $400-$500 to replace this sensor (requires wheel hub replacement). What are the chances that this won't fix the problem? Before the 3 warning lights come on the headlights dim intermittently and there is an intermittent low pitched noise but after the warning lights come on these no longer occur. I am afraid that the problem may be in the ABS control system instead of the sensor. Should I seek out a repair shop (or the dealer?) that can do diagnostics on the ABS system to make sure the wheel sensor is the problem or should I just go ahead and get the sensor replaced and hope for the best? Does a bad or intermittent wheel sensor cause symptoms like I described? Anyone who has had a similar problem and your experience in getting it fixed (or not fixed) would be appreciated.

check the sensor for rust or metal shavings(it has a magnet inside). check the toner ring for damaged teeth. if both check out fine ether replace the wheel sensor or send it off for a full diagnositic(dealership). without the EXACT code thats about all i can say.