Train doors at Front M2 car were not proven closed. TC recycled train doors a few times but to no av ail. Staff(QUE) assisted to push close and isolate the defec tive 'A4' train doors in the Front M2 car in 'close' positio ~~~~~ 1. Fault confirmed/Fault cannot be duplicated Found 2518 A4 doors were isolated. Normalised doors and fault confirmed in depot. Door was slow in closing and unable to close fully. 5cm gap observed. 2. What was found from ER/Fault Trace? ER reflected as reported. 3. Troubleshooting details There are 4 identified causal factors based on FTA: A. Door manifold/actuator faulty - Likely Air leaking continuously from manifold causing door not able to close fully (5cm gap) B. External Obstruction -    Unlikely No signs of FOD was found along guide rails & J-rails. C. Door close sensing switch rigging  - Unlikely After rectifications, conducted 10/20mm gauge - passed. D. Internal Obstruction - Unikely No abnormal resistance in both door movement when isolated. Door push/pull test within criteria. 4. Rectification details Replaced 2518 A4 manifold and preventively replaced the door actuator. Side finding: 2 rollers had cuts. 2 roller had chamfering. Preventively replaced 2518 A4 LHS and RHS rollers. After rectification, door speed satis. Door cyclic test ok, DIR able to extinguish. Door static test ok. Door push/pull test within criteria. N.A/mutalib/lai mk/azli/nazrul/17.02.23