As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 2643, THE CREW REPORTED A LANDING GEAR AIR GROUND FAIL MESSAGE ON TAKEOFF. THE AIRCRAFT RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE NUMBER TWO MAIN LANDING GEAR AFT DOWN & LOCK PROXIMITY SWITCH, OPERATIONALLY CHECKED WITH NO DEFECTS, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.