As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EUG FLIGHT NR 2333: DURING PREFLIGHT, CHECK FIRE DECT WARNING LIGHT AND MASTER WARNING ILLUMINATED AND APU AUTO SHUTDOWN OCCURRED. NO INDICATION OF FIRE NOTED. FAULT LIGHT ILLUMINATED ON APU FPP. APU FUEL VALVE CLOSED, LIGHT (WHITE) ILLUMINATED. MAINTENANCE INSPECTED AND FOUND CIRCUIT BREAKER RIGHT DC ESS 'FIRE DETECT APU IND' OPEN. RESET CIRCUIT BREAKER. C/W AMM TASK 26-13-00-710-801. NO DEFECTS NOTED. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.