As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 2859 - EWR - FLIGHT CREW REPORTED LANDING GEAR AIR GROUND FAIL MESSAGE ON EICAS AND ENGINE 1/2 REV DISAGREE AFTER SELECTING GEAR UP. CREW PERFORMED AIR RETURN AND LANDED AIRCRAFT UNEVENTFULLY. MESSAGES DISAPPEARS WHEN SELECTED GEAR DOWN. EWR MX REMOVED AND REPLACED PROXIMITY SWITCH AND SERVICED NOSE LANDING GEAR. MX PERFORMED OPERATIONAL CHECKS SUCCESSFULLY. AIRCRAFT WAS APPROVED TO RETURN TO SERVICE.