As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU BATTERY OVERHEAT STATUS MESSAGE DISPLAYED ON EICAS. REPLACED APU BATTERY, NO HELP. SIGNAL CONDITIONING CARD REPLACED REF AMM & DIODE 405 POS-12 IN P310 REPLACED REF WDM 24-09-26 PG 1-SHT2, NO MESSAGES PRESENT AFTER 4 HRS OF ACFT POWER -ON-, WITH MULTIPLE SWITCHING OF POWER FROM APU-GND, POWER ON-OFF-ON. APU STARTED NORMAL. REPLACED P310 SCC, TESTED OK NO FAULTS.