As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ON TAXI-OUT BRAKES WOULD MODULATE VIOLENTLY WHEN BRAKES ACTUATED. ECAM MSGS: BRAKES AUTO BRAKE FAULT : BRAKES ANTI-SKID NOSE WHEEL STEERING FAULT. AIRCRAFT RETURNED TO THE GATE. REMOVED AND REPLACED BRAKE STEERING CONTROL UNIT (BSCU) AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 32-42-34, 32-46-00 AND 22-97-00.