DT CX found #2509 BCU fault,FC(315),Ai ~~~~~ DT CX found #2509 BCU fault,FC(315),Air leak test failed,1.0 bar/5min     Further check found #3509 water tank can leak.Replace cap seal o-ring ok.Cut in/out and leak test ok. #2509 BCU suspension pressure fault.Further check ASP pressure on bogie #1 & #2 within criteria and no abnormalities found. Swap ASP transmitter to #1509 for further monitoring.