As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAULT ON LANDING RESTART UNSUCCESSFUL. OIL AT .50. REPLACED THE DEOIL SOLENOID VALVE IAW 49-27-08-404-010 AND EXCITER IGNITION IAW 49-41-03-404-010 DUE TO AN IGNITION UNIT MESSAGE DURING BITE TEST OF APU ECU. SERVICED APU HALF PINT OF OIL AND PERFORMED AN OPS CHECK. NO EVIDENCE OF AN OIL LEAK FOUND. APU STARTED SUCCESSFULLY ON FIRST ATTEMPT. SHUT APU AND RESTARTED. APU STARTED SUCCESSFULLY ON SECOND ATTEMPT AS WELL.