TC reported TIMS showed BCU fault at front M1 car. Fault intermittent . ~~~~~ 1674 TC reported TIMS showed BCU fault. Fault intermittent.  1673 & #1674 found having brake fault. Both cars replaced ACU. Function check & brake cyclic test - OK. No air leak found. Limited movement/depot shunting - OK.  Sarma/Anand/Mohan 44414 ACU S/N :        OLD                NEW #1673   :      1429/011           1539/172 #1674   :      1528/125           1539/171