As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING GEAR EXTENTION WE GOT A CYAN PROX SYSTEM FAULT ALL THREE GEAR CAME DOWN AND THE MESSAGE WENT AWAY THEN DURING TAXI THE MESSAGE REAPPEARED AND WE LOST MAIN BRAKES. BRAKES WERE OUT FOR A FEW SECONDS THEN CAME BACK, NO ISSUES GETTING TO FBO. CORRECTIVE ACTION: REMOVED AND REPLACED PSEU WITH MODIFIED UNIT, FUNCTIONAL CHECK GOOD AT THIS TIME. INSTALLED PN 30227-0404 S/N 0114.