At 45 mph, the abs light and the traction control light turn on. this deactivates both the abs and traction control systems making the car unsafe to drive at over 45 mph. a mechanic diagnosed the problem being crack in the abs sensor ring. although a known issue, mercedes benz, the manufacturer of the smart car, denies any issues with it. the repair that they performed was a replacement of the right axle shaft since they do not import a replacement sensor ring. this is a repair in excess of $700 for a $35 part. that part should not fail within such a relatively low mileage. choosing not to repair could lead to a serious accident at speeds in excess of only 45 mph. *js