As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - ON ENG SHUTDOWN, APU DUCT PRESSURE ZERO WITH APU ON. T/S IAW FIM 36-10-00, FIG 117. STARTED APU. DUCT PRESSURE AT 35 PSI. RAN BOTH PACKS. CHECKS OK. MOTORED ENGINE. CHECKS OK. CYCLED APU AIR SUPPLY VALVE SWITCH. VALVE GOES TO COMMANDED POSITION. SYS CHECKS OK.