AT LOW SPEED , COMING OUT OF A GROCERY STORE PARKING LOT, CAR WENT INTO SUDDEN UNINTENDED ACCELERATION WITHOUT ANY WARNING. FULLY PRESSING ON THE BRAKE FAILED TO SLOW OR STOP THE CAR. WITH THE BRAKE NOT WORKING AND THE CAR ACCELERATING VERY FAST THE CAR BECAME OUT OF CONTROL UNTIL IT CRASHED WITH A LARGE ROCK /BOULDER WHEN IT STOPPED. THERE WAS EXTENSIVE DAMAGE THE THE WHOLE FRONT HALF OF THE CAR. THE CAR HAD TO BE TOWED IN. I SUSTAINED A SIGNIFICANT BRUISES OF MY BREAST BONE AND ADJOINING RIBS. I AM STILL IN PAIN. THIS SAME EXACT MALFUNCTION WITH THIS SAME CAR AS NOTED ABOVE OCCURRED IN 2013. I PAID EXTRA FOR MB TO HAVE AN ENGINEER EXAMINE THE CAR BUT I WAS TOLD NOTHING WAS WRONG. ON BOTH OCCASIONS THE AIR BAGS DID NOT DEPLOY.