What was found
AFTER NORMAL START WITHOUT GPU, WE STARTED TAXIING AND DID THE NORMAL BRAKE CHECK. AFTER MOVING ABOUT 60' ONTO A TAXIWAY I GENTLY APPLIED THE BRAKES AND GOT A YELLOW CAS BRAKE FAIL. THE BRAKES PEDALS THEN FELT AS IF THERE WAS NO PRESSURE. I USED THE PARKING BRAKE TO STOP. TOUBLESHOT TO FAULTY BRAKE CONTROL MODULE, REMOVED AND REPLACED BRAKE CONTROL MODULE IN ACCORDANCE WITH PHENOM 300MM 32-41-07, COMPLIED WITH HYDRALIC SYSTEM OPS CHECK IN ACCORDANCE WITH PHENOM 300MM 29-10-00 NO DEFECTS NOTED. COMPUED WITH BRAKE SYSTEM FUNCTIONAL CHECK IAW MM 32-41-00, NO DEFECTS NOTED, LEAK CHECK PERFORMED NO DEFECTS NOTED,