TC reported obstacle detected at rear DTcar B2 and B4 door. Staff(CTH) checked and confirmed both d oors were working normally. ~~~~~ 3636 TC reported obstacle detected at B2 and B4 door. Staff (CTH) checked and confirmed both doors were working normally. CE 3636 check doors ok. No obstacle detected on Tim display. Depot 3636 B2 & B4 train door operational check.  3636 B2 & B4 Door roller (outer roller)found damaged. Replaced new roller done.Function manually open/closed - OK. Conduct door operation open/close (15x)- OK. DIR extinguished. Checked on door static test open/close - OK.(Within range)    Chan/Aliff/Daniel/Redzwan 45246