As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU AUTO SHUTDOWN WITH FAULT LIGHT WHEN 2 PACK WAS TURNED OFF FOR ENG START. HAPPENED TWICE ONLY FAULT FLAG FOR APU THERMOCOUPLE. STARTED APU AND RAN 15 MINS FULLY LOADED. TEMP WAS WITHIN LIMITS. TRIED SHUTTING DOWN PACKS AND GOT AUTO SHUTDOWN REV FLOW. REPLACED SURGE CONTROL VALVE PER AMM. LK CK GOOD RAN ENG. APU OPS NORMAL AND RT/LT PACK OFF WITH NO SURGE.