TIMS showed BCU fault at Rear M2 car . Train performance - ok. ~~~~~ #2530 Check Tims observed multiple times BCU release fault (FC-312) happen. Check brake frame observed abnormal slow purging to cut off when B1 to coast. Replace ACU and brake cyclic test ok. BCP within criteria. ACU- Old s/n: 1244-106. New s/n: 1008-002. Not: 2274874 raised. Done by Sanip/Koh. 9/05/21.