As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4451 THE CREW REPORTED THAT AFTER TAKEOFF RECEIVED A LANDING GEAR AIR/GROUND FAIL MESSAGE ON EICAS. THE GEAR WOULD NOT RETRACT. THE CREW PERFORMED THE APPROPRIATE CHECKLIST AND ELECTED TO RETURN TO RDU. REMOVED AND REPLACED THE LANDING GEAR ELECTRONIC UNIT IAW AMM 32-32-01. THE OPERATIONAL CHECK WAS GOOD IAW AMM 32-30-00, 32-63-05. NO DEFECTS NOTED. THE AIRCRAFT WAS RETURNED TO SERVICE.