One problem related to brakes failed has been reported for the 2011 Hyundai Sonata Hybrid. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2011 Hyundai Sonata Hybrid based on all problems reported for the 2011 Sonata Hybrid.
As I was gently applying my brakes in heavy freeway traffic, going about 50mph, the brake pedal became soft and dropped to the floor. The brake failure warning light also started to flash and chime. I swerved off to the side of the road to avoid hitting the car in front of me and plowed through some plants on the shoulder prior to coming to a stop with my parking brake.