AT APPROXIMATELY 1500 ON 16 MAR 2010, I USED THE REMOTE TO OPEN THE POWER LIFTGATE ON MY 2007 TOYOTA SIENNA XLE MINIVAN. WHILE LOADING A CHILDREN'S TABLE, THE LIFTGATE STARTED TO CLOSE ON ITS OWN. I TRIED TO PREVENT THE GATE FROM CLOSING AS MY TWO YEAR OLD SON WAS IN THE PATH OF CLOSURE. I HAD TO HOLD THE GATE OPEN AS MUCH AS I COULD AND GRAB HIM AND PULL HIM DOWN AND AWAY TO PREVENT THE DOOR FROM SHUTTING AND POSSIBLY INJURING HIM. IN THE PROCESS, I STRAINED MY BACK. THE SAFETY FUNCTION OF THE POWER LIFTGATE SEEMED TO HAVE STOPPED FUNCTIONING AS WELL. SINCE THE INITIAL FAILURE EARLIER TODAY, THE PROBLEM WITH THE LIFTGATE OCCURS WHENEVER THE POWER FUNCTION IS USED TO OPEN THE DOOR. THE LIFTGATE OPENS AND CONTINUES UNTIL THE LIFTGATE REACHES ITS MAXIMUM OPENING THEN CLOSES ITSELF AUTOMATICALLY. WHEN THE POWER FUNCTION IS DISABLED, THE LIFTGATE FAILS TO REMAIN. OPEN. I HAVE NOT DONE ANY MAINTENANCE OR REPLACED ANY PARTS NOR HAVE I CONTACTED THE TOYOTA DEALER SERVICE DEPARTMENT IN REGARD TO THIS PROBLEM. I HAVE READ ONLINE THAT THIS PROBLEM IS A COMMON OCCURRENCE ON TOYOTA SIENNA MINIVANS WITH MULTIPLE REPORTS OF INJURIES OCCURRING. *TR