TIMS showed BCU fault at Rear M1 car since JUR MT. TC feedback slow pick up when departing station. Train scheduled for stock change at AMK SB. ~~~~~ TIMS showed BCU fault at Rear M1 car sin     #1671-ACU found hunting at exhaust port when put to B1,B2 ,B3.Constant leak when put to coast.ACU c/o. ACU:- New: 1516-095 Old: 1538-168 Not: 2456080 raise. Done by Azwad/Martin/Henry. 26/01/23