As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FIRE DETECT SYSTEM INOP. MASTER CAUTION ANNUNCIATOR PANEL ILLUMINATED WITH MASTER CAUTION LIGHT. APU DETECT INOP LIGHT ILLUMINATED STEADY ON FIRE DETECTION PANEL ON CENTER CONSOLE. REMOVED AND REPLACED APU TAILPIPE DETECTOR IAW AMM 26 15 01 000 802 AND AMM26 15 01 400 802 APU FIRE DET SYS OPS CHECKS GOOD.