As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER APU SHUTDOWN, FIRE WARNING HORN CONTINUED SOUNDING WITH NO LIGHT IN WHEEL WELL. TROUBLESHOT SYSTEM, FOUND APU WARNING MODULE AT FAULT. REMOVED AND REPLACED APU FIRE WARNING MODULE, OPERATION CHECK NORMAL IAW 26-15-00. RETURNED AIRCRAFT TO SERVICE. (K)