What was found
DEN - ON FLIGHT 4438, RETURNED TO GATE. LEFT PACK CAUTION MESSAGE. MAINTENANCE REMOVED AND REPLACED FLOW CONTROL VALVE. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
DEN - ON FLIGHT 4438, RETURNED TO GATE. LEFT PACK CAUTION MESSAGE. MAINTENANCE REMOVED AND REPLACED FLOW CONTROL VALVE. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.