I am also having a brake problem. I was driving one day for about 45 minutes when the brake pedal was extremely hard. It took me about 30 minutes to get back home, but 10 minutes into that drive home the brakes felt fine again. A few day later I took the car out again and stayed close to home in order to test the brakes. After about 15-20 minutes, the brake pedal was hard again and this time the brake light went on. I did some research on this site to try to determine the problem. A few days later, when I got back into the car, the brake pedal was fine. I ran through all the diagnostic tests listed here and passed them all. I then proceeded to take another test drive, and the same thing happened. The brakes were fine for about 15-20 minutes, and then the pedal got hard again. It seems like if the car sits for a day or two the brakes are okay for a short period of time, but I cannot determine the problem based on the tests. Any suggestions would be appreciated.