As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GEAR UP INDICATION & HANDLE MOVED TO OFF. NOSE GEAR RED DISAGREE LIGHT ILLUMINATED & GREEN LIGHT ON UPPER GEAR INDICATION PANEL ILLUMINATED. EMER DECLARED FLIGHT RETURNED & LANDED WITHOUT INCIDENT. ACFT REMOVED FROM SERVICE. REPLACED SENSOR S0853 THAT HAD FAULTED. SYS GND CHECKED NORMAL OPERATION CLOSED.