What was found
APU CSS START FAILED 3 TIMES FL360, FL300, FL290 ON EVERY START THE "FAULT" LIGHT CAME AS EGT PASSED 1000 DEGREES OAT AT 290 -52C DEGREES. GROUNDED - YES. APU BITE PER FIM 49-61 TASK 801 SHOWS CURRENT FAULT 49-72104 "DATA MEMORY MODULE SHOWS CIRCUIT FAILURE" AND FAULT HISTORY SHOWS THREE CONSECUTIVE OCCURRENCES OF FAULT 49-31171 "FUEL CONTROL UNIT FLOW DISAGREES WITH COMMAND". REMOVED AND REPLACED FUEL CONTROL UNIT REF AMM 49-31-11. APU STARTING AND NO FUEL LEAKAGE FOUND. REMOVED FILTER FROM OLD FUEL CONTROL AND NO DEFECT FOUND. ACCOMPLISHED T/S FOR FAULT 49-72104 PER FIM 49-70 TASK 807 - ECU RESET NO HELP AND NO WIRING FAULTS NOTED. REMOVED, REPLACED, AND TESTED APU DATA MEMORY MODULE PER AMM 49-72-11-000-801 & 49-72-11-400-801 - OPS NORMAL. APU BITE PER FIM 49-61 TASK 801 SHOWS NO CURRENT FAULTS.