As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKE OFF, RECEIVED A BRAKE AUTO BRAKE FAULT. DECLARED AN EMERGENCY, AND LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS GROUNDED. REPLACED THE NR 4 MAIN WHEEL TACHOMETER DRIVE SHAFT IAW AMM 32-42-68-400 AND AMM 32-42-00-810-815A. OPS TESTED GOOD.