TIMS showed momentarily BCU control pre ssure fault at RDT car. Fault was self cleared. Performance ok. Fault recurred at CCK2. ~~~~~ Fault trace and FR downloaded into PTU006. Further check found #3645 ACU BCP stuck at 0.25bar during B1 to coast position. Found ACU solenoid v/v exhaust port having air leaking. Swap ACU to #3646 fault was transferred. Replace ACU and function test ok. BCP within criteria. #3645 ACU: Old s/n: 1447-022. New s/n: 1403-002. Not: 2292286 Raised to RSW. Done by Sanip/Koh/Jack. 05/07/21.