One problem related to brake fluid leak has been reported for the 2012 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 Hyundai Sonata based on all problems reported for the 2012 Sonata.
Upon starting the vehicle I received a loud chime and a warning on the small screen on the instrument cluster indicating a brake failure, and that I should not drive the car. The brake pedal went to the floor and there was a very loud grinding and chattering sound coming from the front of the car. There was almost no braking action. I turned the car off and attempted to restart it. The same symptoms occurred. I then checked outside of the car for leaking fluid. There was none. I opened the hood and inspected the brake fluid reservoir and found it approximately 3/4 full of brake fluid. I wiggled the electrical connections to the master cylinder and the fluid connections also. I got back in the car and attempted a restart. The car started without a problem.