As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HMV CK WORKING MCO 127703001, APU QUIT AT GATE BEFORE PUSHBACK. DURING T/S AND JIC OP 6009 FOUND APU FIRE TEST INOP. ALSO, FOUND FIRE LOOP BROKEN WITH APPARENT HIGH HEAT INDICATION AND SOOT INSIDE APU SHROUD AT INNER EXHAUST DUCT CLAMP. REPLACED APU (S/N 36681).