Passenger feedback to staff(CCK) rear M1car B4 door did not open. Staff(BGB) confirmed fault. STaff (JUR) assisted to isolate B4 door at the front M1 car. Passe nger feedback to staff(CCK) rear M1 car B4 door did not open ~~~~~ Passenger feedback to staff(CCK) rear M1 Check the above mention reported and found #1608-A4 RHS door roller damage,replaced roller-done.Security check FOD and clean J-rail & guide rail or rubbing mark-ok.Checked Mating strip,DLS,DCS,DLD,Pull/Push gauge-ok.Door open & close test and static test ok. Done by Saini/Asruddin/Muizzudin. 14/05/23