As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENROUTE KHVN, RECEIVED A "BRAKE ON" CAUTION. PERFORMED ASSOCIATED CHECKLIST; CAUT REMAINED. CYCLED PARKING BRAKE TO SEE IF ISSUE WOULD CLEAR WITHOUT SUCCESS. AFTER CYCLING PARKING BRAK, "PARKING BRAKE FAIL" ANNUNCIATED. COMPLETED ASSOCIATED CHECKLIST. BOTH CAUTIONS REMINAED ON. REMOVED AND REPLACED #4 ELECTROMECHANICAL CONTROLLER UNIT. OPS CHECKED GOOD.