BRAKES FAILED, PEDAL GOES TO FLOOR, ATTEMPT TO PRESS BRAKE PEDAL AGAIN STILL RESULTS IN PEDAL MOVING TO FLOOR WITH NO BRAKING. HIT CAR IN FRONT. 2ND OCCURRENCE. FIRST OCCURRENCE IN JUNE 2011. DEALER SAID THEY COULD FIND NOTHING WRONG. SAME PROBLEM OCCURRED ON 2/21/2012. BRAKES THEN WORK AFTER INCIDENT. FAILURE SEEMS INTERMITTENT. DEALER SERVICE MANAGER SAYS HE THINKS THE PROBLEM COULD BE A MASTER CYLINDER. TOYOTA INVESTIGATING. SO FAR HAD INVESTIGATOR INSPECT CAR BUT HAVE NOT YET AUTHORIZED DEALER TO DO ANY REPAIRS. *TR