As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LHR - INFLIGHT CDG-DFEW. CREW REPORTED CABIN PRESSURE ONE CONTROLLER EICAS MESSAGE WITH NUMBER TWO CONTROLLER ON PLACARD. EMERGENCY DECLARED FLIGHT DIVERTED LHR LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED PRESSURE CONTROL PANEL. SYSTEM GROUND CHECK NORMAL OPERATION.