DT3543/3544: UNDERSHOOT X5DT3543/3544 Encountered undershoot problem on both cabs X5, YCK1, 172830hrs, 1.023m : YIS2, 181656hrs, 1.868m : BGB2, 184503hrs, 1.326m YCK1, 195945hrs, 1.554m and CBR1, 202243hrs, 0.643m. RS event record analysis show BCP abnormalities on DT3544 at all fault timing. Please investigate and follow up, thanks. ~~~~~ 3543/3544: UNDERSHOOT X5 DT3543/3544 Encountered undershoot problem on both cabs X5. YCK1 ,172830hrs, 1.023m : YIS2, 181656hrs, 1.868m : BGB2, 184503hrs, 1.326m, 195945hrs, 1.554m and CBR1, 202243hrs, 0.643m. RS event record analysis show BCP abnormalities on DT3544 at all fault timing. Please investigate and follow up, thanks. Signal refer RS .  543/544 checked all brakes able to release from wheel at 'COAST' position. Checked Fault Record, no BCP/Brake fault on both DT cars. Brake cyclic test & brake pressure check - OK. Compared #3544 brake pressure on TIMS with duplex gauge - OK. Limited movement, no brake fault indication found. OPS 20 raised to follow-up.  Chan SW 44531 To follow up.  543/544 ER D/L & found #2544 brake pressure high. 2544 Replaced ACU & checked for any leakage - OK. Brake cyclic test - OK.  Jervis 44531 2544 ACU S/N : OLD : 1047/083 NEW : 1301/121