As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: PARKING BRAKE FAILED WHEN STOPPED ON TAXIWAY. THEN FAILED AGAIN ONCE AT GATE. AIRCRAFT ROLLED ABOUT 6 INCHES AT SHUTDOWN CHECKLIST UNTIL CHOCKS INSERTED. MAINTENANCE FOUND LOOSE CONNECTOR ON ELECTRIC PARK BRAKE VALVE 102GG, SECURED CONNECTOR AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 32-45-00.