As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TRANSIT CHECK, FOUND 30 PSI INDICATION IN LT SYSTEM WITH BOTH ISOLATION VALVES IN THE CLOSED POSITION AND APU SHUTOFF VALVE IN THE OPEN POSITION. FOUND LT ISOLATION BYPASS CHECK VALVE SPRING BROKEN. REMOVED AND REPLACED BYPASS CHECK VALVE, IAW AMM 36-11-05. LEAK CHECK AND OPERATIONS CHECK GOOD. NO DEFECTS NOTED AT THIS TIME.