As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AFTER TAXI OUT PILOT STOPPED ON TAXIWAY FOR TRAFFIC WENT TO THROTTLE UP AND AC WOULD NOT MOVE. PASSENGERS WERE DEPLANED ON THE TAXIWAY AND TRANSPORTED TO THE TERMINAL BY BUS. MAINTENANCE REPLACED THE BRAKE STERRING CONTROL UNIT 10GG (BSCU) AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 32-42-34.