As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AS AIRCRAFT WAS RELEASED FOR FLIGHT, THE PILOT RELEASED THE PARKING BRAKE, ACTIVATED THE REGULAR BRAKE SYSTEM AND NOTICED THE PRESSURES ROSE TO 1,000 PSI AND FELL OFF TO NEAR ZERO. AFTER SEVERAL ATTEMPTS TO CHECK THE SYSTEM THE PILOT CONTACTED MAINTENANCE CONTROL AND WAS ASKED PERTINENT QUESTIONS. THE AIRCRAFT WAS PLACED BACK IN BLOCKS AND SHUT DOWN. INITIAL TROUBLESHOOTING POINTS TO THE NORMAL BRAKE CONTROL VALVE.