TC reported train doors was not proven closed at Rear M1 A3 door. Staff(BSH) assisted and reported n o abnormalities. TC recycled train doors a few times to clea r fault. ~~~~~ Reported as Level 3. L3   #1685-A3 door fault code 023-saloon door A3 close operation time out. ER & fault trace download PTU 007. Check wiring between the car to DCP and DO ok. Mating strip within criteria. Push/Pull resistant LHS/RHS- 4.6 - 4.8kg. Remove the door and inspect the side and corner for any deformation of seal-ok. Found 1 big & small LHS door roller give way against the roller bearing. Done by Jack/Sanip/Koh. 08/11/20. #1685-A3 door LHS replace 2 big roller, 1 small roller. RHS replace 1 big roller. Door mating: Top=63.1, Mid=64.2, Bottom=63.8. Push pull gauge LHS=4.0. RHS=4.2. DCS to pate=14.8. Door fuction check-door open having issue, fault code 062. Found door locking device having issue.    Done by Haslan/Saini/Zulq/Din. 11/11/20. #1685-A3 DLD faulty. Replaced DLD. Carried out door cyclic/function test ok. Door Lock Device: New s/n: C151 BDL 156003. Old s/n: C151 BDL 165067. Not: 2218785 raised.. Done by Koh/Joshua. 12/11/20.