What was found
AFTER TAKEOFF APPROXIMATELY AT 500' AGL, GOT A MASTER CAUTION ECAM MESSAGE FOR FADEC 2 FAULT. COMPLIED WITH CHECKLIST. RETURNED TO KMEM BECAUSE OF KBTR SHORT RW AND CAUTION ABOUT OVERBOOST WITH REVERSE THRUST. REMOVED AND REPLACED NR 2 ENGINE ECU REF A300-600 MM 73-21-01-4-05 STEPS 1 THRU D-4. REQUIRES IDLE SPEED TEST. WHILE TROUBLESHOOTING FADEC FAULT AND PERFORMING FADEC BITE TEST ON MX PANEL, UNABLE TO PAGE FWD FOR FAULT INDICATION, THUS REPLACED ECU AS STATED ABOVE AND NOW ABLE TO PAGE FWD, NO FAULTS LISTED AT THIS TIME. REQUIRES IDLE SPEED TEST. NR 2 ENGINE IDLE SPEED TEST GOOD IAW FEDEX A300-600 AMM 73-21-01-4-05 AND 71-00-00-5.