As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING APU COLD SOAK START AT FL400, APU FAULT LIGHT ILLUMINATED. APU FAILED TO START, ACCOMPLISHED QRH. FAULT LIGHT WENT OUT IN 5 MINUTES. REATTTEMPT MADE AT FL 350 SUCCESSFUL. ACFT GROUNDED. FAULT ON APU READS, 49-31016, OVERTEMP SHUTDOWN. SUBSEQUENT STARTS FAULT DOES NOT SHOW. A SECOND CSS WAS ACCOMPLISHED WITH NO ISSUES.