As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE CREW REPORTED APU FIRE MESSAGE DURING APU START. MESSAGE WENT AWAY AFTER APU GOT TO FULL SPEED. CREW SHUT DOWN APU AND CONTINUED FLIGHT. INSPECTED APU, NO SIGN OF FIRE AND CLEANED THE APU FIRE LOOP CONNECTOR AND OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.