As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON POWERING UP COLD PLANE ACFT PRESSURIZATION SYSTEM INDICATED AUTO FAIL & ALTN MODE. WHEN TRANSFERRING FROM APU TO GROUND PWR AUTO FAIL & ALTN MODE FLASH ON AND GO OUT. COMPLIED WITH FIM 21 31 TASK 801. NO FAULTS FOUND. AIRCRAFT OK FOR SERVICE.