As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - L DUCT PRESSURE ONLY 8 PSI AFT IDLE PWER TOP OF DESCENT. REACTIVATED LT ENG HIGH STAGE VALVE & CONTROLLER. REFER TO ITEM NR54 LOG PG 398231. R & R LT AIR SUPPLY CONTROL CARD IAW AMM 35-11-12. OPS CHECK GOOD. OPS CK OK ON GND.