What was found
NO DUCT PRESSURE FROM APU. TRANSFERED TO MDDR 134869, DDG 49-11-01-01, CAT C. PERFORM FIM TASK 49-11 FT 981 UP TO BLOCK 26, NO DUCT LEAK NOTED AND NO DEFECTS NOTED. STANDBY C-72L/11R DYBY W 10L/9R DUCT PRESSURE WITHIN 2 PSI. REMOVED AND REPLACED APU CONTROL UNIT (ECU), IAW AMM 49-61-05. REACTIVATED APU SHUT OFF VALVE. PERFORMED ENGINE RUN. OPS CHECK DUCT PRESS WITH BOTH PACS ON, IAW AMM 49-11-00, OPS CHECK IS NORMAL AT THIS TIME. ENG RUN PER AMM 71-00-00. PLACARDS REMOVED. THIS CLOSES DMI 134869.