As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW RECEIVED A CABIN DOOR OPEN MESSAGE ON EICAS. NO OTHER INDICATION THAT DOOR WAS OPENED. CREW FOLLOWED QRH PROCEDURES, DECLARED AN EMERGENCY AND LANDED WITHOUT INCIDENT. MAINTENANCE WAS DISPATCHED. TROUBLESHOT SYSTEM AND FOUND PROXIMITY SENSOR NOT WORKING DUE TO AN INOPERATIVE WIRING HARNESS. MAINTENANCE CONTROL PLACED DOOR INDICATION SYSTEM ON MEL AND RETURNED THE ACFT TO SERVICE. (S)