As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 146, PHX-LIH: AFTER TAKEOFF AND GEAR SELECTED TO 'UP' POSITION, RECEIVED GEAR DISAGREE LIGHT. SELECTED GEAR DOWN AND RECEIVED DOWN AND LOCKED INDICATIONS. FLIGHT RETURNED TO PHX. MAINTENANCE REPLACED THE LEFT MAIN LANDING GEAR RETRACTION ACTUATOR.