3552 has numerous BCU release fault. ~~~~~ 3552 has numerous BCU release fault. BCP 0.63bar at Coast/powering. To check and rectify, suspect ACU faulT. Request by OE-Tan HS.  3552 ER D/L & found FC 312 (BCU release fault). Found ACU faulty & replaced - Done. Function test brake pressure - OK. No residue pressure at 'COAST' & no air leak. 3552 ACU S/N : OLD : 1302/049 NEW : 12/49/045  Sarma/Kiran 43991