TC reported BCU fault momentarily appeared on TIMS when train departed station and train was moving at a slow speed. Subsequently fault self cleared and train p roceeded in AM mode to next station. ~~~~~ 3570 TC reported BCU fault momentarily appeared on TIMS when train departed station and train was moving at a slow speed. Subsequently fault self cleared and train proceeded in AM mode to next station. CE checked 3570 no BCU fault found n train performance ok. Depot 3570 brake operational check.  3569 BCP unable to release. FC BCP Bog 1 & 2 fault. Swapped ACU from #3569 to #3570. Replaced ACU on #3570 & security check - OK. Swapped BCU from #3569 to #1569 as precaution. Conducted brake pressure test & no fault light illuminated. Brakes able to release when at COAST position.  Aliff/Redzwan 45163 ACU S/N : (after swapped) #3569 - 1241 044 #3570 - 1302 049 (NEW) #3570 - 1311 060 (faulty) BCU S/N : (after swapped) #3569 - 1816 159 #1569 - 1811 086