One problem related to brake sensor has been reported for the 2006 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Hyundai Sonata based on all problems reported for the 2006 Sonata.
The car either accelerating or braking jerks as if it starts and stops on it's own. I am afraid of driving it. I've had it to the dealer a couple of times and my first complaint was that it jerked into gear. It didn't matter if reverse or forward. The check engine light will come on. The dealer replaced a shift sensor but that didn't fix the check engine light nor the stop and start at random times. When this happens the car slows way down and I barely can get it to go forwards. The last time it happened was at night. I pulled onto a street from a stop sign into traffic. I barely went half a block and had to pull into a driveway to get out of the traffic behind me. The esc light came on briefly on the dash. I looked at the off switch and it was illuminated. I pushed it off I think. The road was dry and there was no reason that turning at 5 mph would create a reason for such a reaction from the car. I only have 30k miles on the vehicle. It should not be doing this.