As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FIRE MASTER WARNING MESSAGE RECIEVED ON GROUND. APU AUTO SHUTDOWN. BOTTLES DID NOT DISCHARGE. TURNED OFF MASTER BATTERY. PERFORMED DOOR RIGGING PROCEDURE IAW AMM 49-14-19. DOOR WILL NOT CLOSE AFTER OPENING. REMOVED AND REPLACED THE APU INLET DOOR ACTUATOR IAW AMM 49-14-16. OPS CHECKED GOOD, NO DEFECTS NOTED AT THIS TIME. ACFT OK FOR SERVICE.