As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI, PNEUMATIC PRESSURE WENT TO 200 PSI RESULTING IN LOSS OF BRAKES AND STEERING. THE LANDING GEAR SELECTOR VALVE WAS DETERMINED TO HAVE CAUSED THE LOSS OF PNEUMATIC PRESSURE. THE VALVE WAS REPLACED AND THE A/C RETURNED TO SERVICE.