As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHX - FLIGHT 2899, THE CREW REPORTED A LANDING GEAR AIR GROUND FAIL MESSAGE ON CLIMB AND THE GEAR WOULD NOT RETRACT. THE AIRCRAFT RETURNED TO PHX WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE AIRCRAFT, RESET THE AIR GROUND SYSTEM, OPERATIONALLY CHECKED WITH NO DEFECTS AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE. (A)