As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAILED TO START. GROUNDED - YES. CW FIM PROCEDURES & NOTED FAULT CODE 49-15004 - INLET DOOR SHUTDOWN. FOUND APU INLET DOOR ACTUATOR INTERMITTENT. REF B737-800 FIM 49-10 TASK 806 & B737-800 WDM 49-62-11. REMOVED AND REPLACED APU AIR INLET DOOR ACTUATOR REF B737-800 AMM 49-15-31. OPERATIONAL TEST GOOD.