As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A RIGHT HAND AIR CONDITIONING PACK FAIL WARNING MESSAGE ILLUMINATED, DURING THE TAXI OUT FOR TAKEOFF. THE AIRCRAFT RETURNED TO THE GATE. MAINTENANCE INSPECTED AND REPLACED THE RIGHT HAND NACA DUCT CHECK VALVE, IN ACCORDANCE WITH DORNIER MAINTENANCE MANUAL 21-51-24. OPERATIONAL CHECKS WERE COMPLETED AND THE AIRCRAFT WAS RETURNED TO SERVICE.