What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT DIVERTED TO PLS DUE TO A FUEL USED / FUEL ON BOARD DISAGREE ECAM MESSAGE. FLIGHT CREW ACCOMPLISHED FUEL LEAK PROCEDURE AND REPORTED THAT AT DIVERSION FUEL INDICATED IN LEFT TANK WAS OFF BY 1300 LBS. FROM RIGHT TANK. THE AIRCRAFT LANDED SAFELY AT PLS WITHOUT FURTHER INCIDENT. MAINTENANCE PERFORMED WALK AROUND AND VERIFIED NO FUEL LEAKS PER TSM 28-11-00. PERFORMED FUEL TRANSFER PER AMM 28-25-00 AND VERIFIED QUANTITIES CHECKS GOOD. ACCOMPLISHED TSM 28-11-00 FOR FUEL QUANITY INDICATION COMPUTER AND ALL QUANITIES CHECK OK.