As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AT RUNWAY HOLD PARKING BRAKE WOULD NOT RELEASE AND DISABLED THE AIRCRAFT ON ACTIVE TAXIWAY. MAINTENANCE BLED THE PRESSURE OFF AND THE AIRCRAFT RETURNED TO THE GATE. REPLACED PARKING BRAKE ELECTRICAL CONTROL VALVE AND ACCOMPLISHED A SATISFACTORY LEAK / OPERATIONAL CHECK PER AMM 32-45-51