TC reported TIMS displayed BCU fault at rear M2. Fault self-cleared ~~~~~ Checked #2666 fault code 312, 308, shown BCU fault. Found leak from ACU exhaust port, replaced ACU. Brake cyclic test/function tested ok. ACU- New s/n: 1528-132  Old s/n: 1538-154. Not: 2129975 raised to RSW. Done by Omar. 11/02/20.