TC reported Rear DT BCU unit healthy fault indication light up intermittently. TC did brake status c heck at CBR1, confirmed no stuck brake indication. Train per formance - ok. ~~~~~ #3562 Fault code multiple 327 (BCU Speed probe 4), FC323 & 322 fault confirm #3562 show BCU unit fault. Check Tacho 1, 2, 3 ok. Found Tacho 4 O/L. Replaced Tacho 4. Limited movement & depot shunting, no recurrence of fault. Not: 2228854 raised. Tacho 4: New s/n: 0411015. Old s/n: 1249225. Done by Saini/Asruddin/Koh/Zulq. 13/12/20.