As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ON APPROACH INTO STL AMBER ECAM MESSAGE FOR ALTERNATE BRAKE FAULT, CREW FOLLOWED NON-NORMAL PROCEDURES, ACCOMPLISHED A GO AROUND AND DECLARED AN EMERGENCY. AIRCRAFT LANDED AT STL WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE ALTERNATE BRAKING CONTROL UNIT PER AMM 32-43-34. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED.