As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 3946 DURING TAKEOFF THE CREW REPORTED THEY RECEIVED AN EICAS LANDING/GROUND AIR FAIL MESSAGE. THE CREW RAN THE CHECKLIST AND DECLARED AN EMERGENCY. THE CREW RETUNRED TO ORD AND LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. THE OPERATIONAL CHECK WAS GOOD ON ALL WEIGHT ON WHEELS PROXIMITY SENSORS IAW AMM 32-63-05. REMOVED AND REPLACED LANDING ELETRONIC GEAR UNIT IAW AMM 32-32-01. THE OPERATIONAL CHECK WAS GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.