As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE MASTER WARNING IS INTERMITTENTLY ILLUMINATING. IN CONJUNCTION WITH THE WARNING LIGHT, THE BAGGAGE AFT VENT INLET VALVE OUTLET CLOSED. GUARDED SMOKE EXTG AND FIRE BOTTLE AFT ILLUMINATES. REMOVED AND REPLACED AFT CARGO AFT SMOKE DETECTOR PER Q400 AMM 26-12-01-400-801. OP'S CK GOOD. RETURNED TO SERVICE.