What was found
DURING FLIGHT, THE "APU FAULT" MESSAGE WAS SHOWN AT ECAM SYSTEM DISPLAY, THE ELECTRICAL GENERATOR NO 1 HAD BEEN DEFERRED (MEL 24-22-01) AND THEREFORE THE AIRCRAFT RETURNED FROM FLIGHT. DURING THE MAINTENANCE ACTIONS AND ACCORDING TO THE TROUBLESHOOTING TSM TASK 49-62-00-810-815-A. THE APU OIL COOLER WAS FOUND DEFECTIVE AND IT WAS REPLACED AND THE TEST WAS SATISFACTORY IAW AMM 49-91-44-000-801-A AND AMM 49-91-44-400-801-A. THE ELECTRICAL GENERATOR NR 1 WAS REMOVED AND REPLACED AND THE TEST WAS SATISFACTORY IAW AMM 24-21-51-000-804-A, AMM 24-21-51-400-804-A AND AMM 24-21-00-710-809.