TC feedback TIMS showed BCU fault at Rear M1 car. Fault self cleared. Train performance - ok ~~~~~ #1521-Having FC 330, 331, 308. BCU fault. Replaced BCU and wheel diameter set to 833mm tested ok. BCU-New s/n: 1808036.  Old s/n: 1745016. Done by Low K.H./Henry. 22/08/20. #1521 Brake cyclic test found ACU air leak from exhaust port when B1 to coast. Replaced new ACU and brake cyclic test ok. No ACU air leak. BCP within criteria. Depot shunting, no reoccurance of BCU fault. ACU-New s/n: 1037-055.  Old s/n: 1008-004. Not: 2192313 raised to RSW. Done by Zulq/Saini/Koh/Din. 23/08/20.