As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE AIR SYSTEM FAULT. COMPLIED WITH COM PROCEDURE LEAVING THRUST LEVER 2 AT IDLE UNEVENTFUL AIR RETURN TO ORD. VISUALLY INSPECTED BUFFER AIR SYSTEM IAW TSM 75-26-00-810-819-A. FOUND LOOSE CONNECTION TO BIFFER AIR VALVE PRESSURE SENSOR. TIGHTENED PNEUMATIC LINE IAW AMM 75-26-22-400-801-A. OPS CHK GOOD. NO FURTHER DEFECTS NOTED AT THIS TIME