What was found
ON FLIGHT 4188, CREW REPORTED WHILE EN ROUTE "LO FUEL NR 2" WARNING WITH NR 1 TANK ON EICAS SHOWING BLANK. CLEARED IT SELF THEN REAPPEARED. FUEL QUANTITY ON FMS SYSTEM ALL NORMAL. APPROACHING ORD, ANOTHER WARNING AND NR 2 FUEL ON EICAS SHOWED BLANK. DECLARED EMERGENCY/PRIORITY APPROACH AND LANDED SHORTLY AFTER. AIRCRAFT REMOVED FROM SERVICE. FOUND REFUEL PANEL POWER SWITCH IN "BATTERY" POSITION. RESET POWER SWITCH TO "POWER" POSITION. OPERATIONAL CHECK GOOD AND NR 8194; AIRCRAFT RETURNED TO SERVICE.