VEHICLE IS CURRENTLY PARKED AT DEALER WITH CONFIRMED BRAKE/WHEEL LOCKING PROBLEM OCCURRING IN ONE WHEEL AT TIME AND RANDOM AMONG 3 OF THE 4 WHEELS EACH TIME APPLIED IN MODE SIMILAR TO ABRUPT STOP AND IN SLICK CONDITIONS.THIS BRAKING PROBLEM DID RESULT IN AN ACCIDENT 11/18/2013. THE COMPUTERS INDICATE EVERYTHING WORKING PROPERLY YET TECH'S ARE ABLE TO CONFIRM THAT IS NOT THE CASE. AFTER NUMEROUS TESTS, DEALER TECH'S WERE ADVISED BY NISSAN TO CEASE FURTHER TESTING AND OPEN CASE WITH CONSUMER AFFAIRS. INITIAL BRAKE ISSUE REPORTED 8/7/2012. BRAKE PEDAL WENT ALL THE WAY TO THE FLOOR. DID NOT HAPPEN EVERY TIME BUT FREQUENT. CAUSED INCONSISTENT STOPPING CONTROL AND ALMOST CAUSED ACCIDENT DRIVING AND EVEN PULLING A PARKING SPOT. DEALER REPLACED MASTER CYLINDER. VEHICLE WAS AGAIN RETURNED TO DEALER 12/26/2012 FOR SOFT/SPONGY BRAKE PROBLEM BRAKES WOULD GO ALL THE WAY TO THE FLOOR WITH UNSAFE AND REDUCED BRAKING ABILITY. DEALER HAD VEHICLE UNTIL 1/4/2013. APPEARS THEY REPLACED MASTER CYLINDER AGAIN, TO NO AVAIL. THEY CONTACTED NISSAN TECH-LINE FOR ASSIST. REPLACED ABS CONTROL MOD ASSY AND BRAKES APPEARED NORMAL AGAIN. 6 DAYS LATER ON 1/10/2013. STREET WAS SNOW COVERED. I LIGHTLY APPLIED BRAKES & VEHICLE BEGAN TO LOSE CONTROL, WITH REAR OF THE VEHICLE TRYING TO COME AROUND. THE VEHICLE FELT LIKE A WHEEL OR BRAKE LOCKED UP CAUSING ME TO BEGIN SLIDING, THEN LIKE TRACTION CONTROL WAS MALFUNCTIONING CAUSING FURTHER LOSS OF CONTROL. THEY CHECKED IT & CONCLUDED EVERYTHING WAS WORKING PROP