As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JFK - INFLIGHT ORD-CDG. CREW REPORTED AFTER TAKEOFF LEFT ENGINE PRESSURE REGULATING VALVE EICAS WITH MASTER CAUTION LIGHT. ACCOMPLISHED QRH PROCEDURE AND SHUT OFF LEFT PACK. AIRCRAFT REMOVED FROM SERVICE. REPLACED PRESSURE REGULATING VALVE ON LEFT ENGINE. SYSTEM GROUND CHECK NORMAL OPERATION.