1555 DURING DT CHECK FOUND BCU FAULT. ~~~~~ 1555 DURING DT CHECK FOUND BCU FAULT.  1555-FC BCU BCP Fault. ER Shows 15555 slow to release.    Brake cyclic test found 1555 TIMS BCP slow to release at coast. Install 2555 ACU to 1555. Replaced 2555 with new spare ACU. Brake cyclic test - OK. Brake function checked - OK. No air leak on solenoid v/v. No residual pressure at coast . Limited movement - OK. After swop ACU s/n: 1555:1236/090 2555:1301/125 Faulty ACU S/N: 1555:1024/033 Kamarul/Shafie/Sarma/Anand/Alan 44872