As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CHECK FIRE DETECTOR CAUTION LIGHT CAME ON TWO TIMES IN QUICK SUCCESSION. MASTER WARNING LIGHT ILLUMINATED AT SAME TIME, NO OTHER LIGHTS ILLUMINATED. REPLACED APU FIRE BOTTLE, OPS CHECKED GOOD NO DEFECTS NOTED. OPS CHECK FLIGHT GOOD. RETURNED TO SERVICE.