As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - APU FAULT EICAS MSG LT CAME ON AFTER APU WAS "ON" & RUNNING FOR APPORX 3-5 MIN APU SHUTDOWN. SECOND START NORMAL. FOUND "GEN FILTER" FAULT. PERFORMED FIM 49-11-00, FIG 112 RESISTANCE CHECK & CONTINUITY CHECK OK. REPLACED ECU AMM 49-61-05, APU CHECK OK NO FAULTS NOTED.