WAS DRIVING HOME FROM RUNNING ERRANDS, ABOUT A 4 MILE DRIVE AT 35 MILES/HR. AT A STOP LIGHT THERE SEEMED TO BE SOME SORT OF ELECTRICAL SURGE. ALL THE DASHBOARD LIGHTS FLASHED AND THE VEHICLE TURNED OFF. I WAS ABLE TO PUT THE CAR IN PARK AND RESTART IT. THERE WERE NO WARNING LIGHTS ON AFTER RESTARTING THE ENGINE, SO I ASSUMED IT WAS A FLUKE AND CONTINUED ON MY WAY HOME. A LITTLE FURTHER DOWN THE ROAD AT ANOTHER STOP LIGHT IT HAPPENED AGAIN. I PULLED INTO MY DRIVEWAY AND STARTED TO UNLOAD MY CAR WHEN I NOTICED SMOKE EMANATING FROM UNDER THE HOOD. I OPENED THE HOOD TO DISCOVER A SMALL FIRE COMING FROM A LARGE GROUP OF WRAPPED WIRES BEHIND THE BATTERY. I WAS ABLE TO PUT IT OUT QUICKLY WITH A FIRE EXTINGUISHER, BUT THE CAR IS COMPLETELY DEAD AND THE ENTIRE ELECTRICAL HARNESS NEEDS TO BE REPLACED AS WELL AS SOME OTHER NEARBY PARTS. THIS VEHICLE WAS WELL TAKEN CARE OF. THERE IS JUST UNDER 65,000 MILES ON IT AND I BROUGHT IT IN FOR IT'S 60K MAINTENANCE 6 MONTHS AGO (6/11/18). AT THAT TIME THEY ALSO TOOK CARE OF THE RECALLS FOR THE PASSENGER SIDE AIRBAG AND THE POWER SLIDING DOORS. SINCE I WAS ABLE TO CONTAIN THE FIRE QUICKLY, THIS VEHICLE SUFFERED MINIMAL ENGINE DAMAGE, SO I'M WONDERING IF IT SHOULD BE USED FOR INVESTIGATION PURPOSES BEFORE REPAIRS ARE MADE AS IT APPEARS THIS MAY HAVE HAPPENED WITH OTHER TOYOTA SIENNAS THAT SUFFERED MUCH GREATER DAMAGE.