As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PUSHBACK APU FIRE WARNING CAME ON APU SHUTDOWN AND INDICATION EXTINGUISHED APPROXIMATELY 2 MINUTES LATER. FIRE INDICATION RETURNED AND REMAINED ON. CREW FIRED APU EXTINGUISHER BOTTLE AND FIRE LIGHT DID NOT GO OUT. INSPECTED APU AND COMPARTMENT AREA NO EVIDENCE OF FIRE NO EVIDENCE OF FIRE DETECTED BY GROUND OR FIRE RESPONSE PERSONNEL. DEFERRED APU FIRE DETECTION AND EXTINGUISHING SYSTEM TO MEL, APU INOPERATIVE. TESTED FIRE LOOP SYSTEM, UNABLE TO DUPLICATE PROBLEM.