As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU WOULD NOT START IN FLT. REPLACED APU INLET DOOR RELAY (K176). OPERATED INLET DOOR NUMEROUS TIMES WITH NO DISCREPANCIES & INSP. INLET DOOR FAIRING AND LINKAGE. RECOMMEND REPLACING ECU BOX (PRECAUTIONARY). REPLACED APU CONTROLLER, OPS CHECK OK.