As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU CSS COMPLETED LESS THAN ONE HOUR PRIOR TO TOP OF DESCENT. FIRST ATTEMPT AT FL380 WAS UNSUCCESSFUL WITH A FAULT LIGHT. SECOND ATTEMPT AT FL380 WAS UNSUCCESSFUL WITH THE FAULT LIGHT. THIRD ATTEMPT AT FL310 HAD A SUCCESSFUL START. ACFT GROUNDED. REPLACED APU IAW T/C 78349-1- AND AMM 49-11-00-400-803 TC 78349015, 78349008, 78349001, 78349000, 78349016.