Intermittent BCU fault at car 1521(FrontM1). ~~~~~ 521/522 ER D/L & found fault at 2521. Swopped ACU from 2522 to 2521 & new ACU installed at 2522. Brake pressure test - OK. ACU S/N (Original) : 2521 : 1037-055 2522 : 1236-093 NEW  : 1310-138 (Installed at #2522)  Selvan/Lee PT. 03/09/2020.