TIMS showed BCU brake fault at Front M2car. No other fault indications. Train performance - ok. Fau lt self cleared after departing NEW1. ~~~~~ 2561 TIMS showed BCU brake fault. No other fault indications. Train performance - ok. Fault self cleared after departing NEW1.  2561 ACU replaced as instructed. Security/function check - OK. 2561 ACU S/N : OLD : 1310/139 NEW : 1037/055  Alan 44080