As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED A LG AIR/GND FAIL EICAS MESSAGE DURING CRUISE. IT WAS FOLLOWED BY AN E1/E2 REV DISAGREE MESSAGE. THE QRH WAS FOLLOWED AND IT WAS DECIDED TO RETURN TO FNT DUE TO ICING CONDITIONS AT THE DESTINATION. THE MESSAGE APPEARED INTERMITTENTLY DURING DESCENT AND CLEARED AFTER GEAR EXTENSION. THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE NOSE PROX SWITCH TO HAVE A PIN BROKEN OFF IN THE CONNECTOR. THE PIN WAS EXTRACTED FROM THE CONNECTOR AND THE PROX SWITCH WAS REPLACED WITH NO FURTHER DEFECTS NOTED.