As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE NR 3 ENGINE FIRE WARNING LIGHT ILLUMINATED AFTER TAKEOFF. THE EMERGENCY CHECKLIST WAS COMPLIED WITH AND THE WARNING LIGHT WENT OUT. THE AIRCRAFT WAS RETURNED TO PHX WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE NR 3 ENGINE 13TH STAGE BLEED AIR DUCT TO EJECTOR VALVE BLOWN. THE DUCT WAS REPLACED, THE ENGINE WAS RUN AND ALL CHECKS WERE GOOD.