As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING APU CSS AT FL380, APU FAULT LIGHT ILLUMINATED. FOLLOWED QRH PROCEDURE AND ACCOMPLISHED RESTART AND PASS CSS AT FL350. ACFT GROUNDED. COMPLIED WITH APU BITE PROCEDURE, REF AMM 49-61-00-700-801. NO FAULTS FOUND ON CURRENT STATUS. APU FAULT HISTORY SHOWS MAINT MESSAGE 49-41010. NO ACCELERATION SHUTDOWN, 1 START OLD. APU STARTS AND OPS NORMAL ON GROUND. APU REMAINS ON MEL 49-99A, REF LOG PAGE 11596413.