One problem related to brake antilock wheel speed sensor has been reported for the 2009 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2009 Hyundai Sonata based on all problems reported for the 2009 Sonata.
I had to replace the rear brake pads and rotors. The rotors were warped from the pads constantly rubbing on them. Clearly there is a problem here with the number of complaints I see. My mechanic could not believe the damage done to the rotors and told me the front brakes usually wear first. I have also had the vehicle in twice for the rough done shifting that occurs when the vehicle is cold. The dealership reprogrammed the transmission both times but that did not solve the problem. I also had a problem with the esc light staying on but the dealership replaced the rear wheel speed sensor.