As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5505, CMH TO IAH. DURING CRUISE THE FLIGHT CREW RECEIVED AN APU CROSS FLOW FAIL MESSAGE FOLLOWED BY A FUEL IMBALANCE. THE AIRCRAFT CONTINUED TO TRANSFER FUEL TO THE NR 2 TANK AND THE FLIGHT DIVERTED TO SDF WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT THE SYSTEM AND FOUND THE APU FUEL CROSS FLOW SHUT-OFF VALVE WAS AT FAULT. THE VALVE WAS REPLACED AND THE FUEL SYSTEM OPERATED NORMALLY.