DT546 undershoot dershoot at XPO1 2026hrs due to brake blending. Unable to take RS logs e to possible faulty event recorder. ~~~~~ ER downloaded - found 2545 BCU fault (FC308, 330, 331)    BCP unable to release EM to coast. - fault could be duplicated. Replaced ACU and function tested ok. Preventively swapped 2545 BCU to 1545.  /KUMAR/02.04.22