TC reported FM1 intermittent BCU fault when train is moving. Train performance ok. ~~~~~ TC reported FM1 intermittent BCU fault w     ACU was previously swapped from #2534 for similar fault.Check Tims FC-312/330/331/308,Brake cycle observed BCP on car #1552 was slow release and brake frame found ACU exhaust port heavy air leaking during brake cycle.ACU send to brake shop for to replace diaphragm and bonded valve.ACU install and brake function test ok.BCP within cateria,no observed any slow release or air leaking. #1552 ACU (use back)    Old s/n: 1042-070 New s/n: 2350139 Done by Koh/Faddzal/Sanip.  19/01/22