TIMS showed BCU fault at car 1712. TC perform brake status checked and confirm rear M1 brake fault. train return back to depot. TIMS showed BCU fault at car 171 2. TC perform brake status checked and confirm rear M1 brake ~~~~~ TIMS showed BCU fault at car 1712. TC pe   Checked TIMS #1712 found FC 340 BCU ASP out of range M1 bogie 1, fault unable to be duplicated in depot. Brake self-test both DT cab ok. EP2002 brake logs show low BSR during fault reported timing for #1712 bogie 1. Replaced #1712 bogie 1 rio valve as preventive measure. Brake function test and self test ok. Notification to CSC: 2585542. Done by: Rizman, Sanip, Koh, Jack (2/4/24)