What was found
FLT#1388, LAX-BOS. (ETOPS) 'APU FUEL LO PR; REMOVED AND REPLACED APU FUEL LP SWITCH IAW AMM 28-22-14. NO HELP. SLAVED APU FUEL VENT RELAY (6QC). NO HELP. MOVED DEFECT TO LP 4027778-2 (REMOVED AND REPLACED APU FUEL PRESSURE SWITCH (7QC) IAW AMM 28-22-15. NO HELP. SLAVED ECB - ELECTRONIC CONTROL BOX, NO HELP. MOVED DEFECT TO LP 4027779-1(ITEM PLACED ON MEL 49-10-01B CAT C MX-4 UPDATED PLACARDS INSTALLED)); REMOVED & REPLACED APU FUEL PUMP REF AMM 28-22-51 & OPS CHECK GOOD. LEAK CHECK GOOD. THIS ACTION CLEARS THIS MDDR, MX-4 UPDATED & MCC NOTIFIED.