Train doors at front M1 car were not proven closed. TC recycled train doors a few times but to no av ail. Staff(OTP) notified that there were no abnormalities wi th aforementioned doors. Pax was disembarked at OTP EB. DIRB ~~~~~ Fault confirmed in depot. Train returned with door slightly ajar with 25mm gap. Function test was carried out and found door was intermittenly not able to close. From ER observed TC cycled doors afew times but door unable to close. Check and found manual movement of door leafs with high resistance. Found 1501 A3 doors required above 20kg force. Found both door leafs door bracket slightly misaligned with door actuator. No air leakages from actuators and manifold in open/closed position. Door leaf manual movement when connected to actuator found with high resistance. Inspected door rollers for both A3 door leafs and found SATIS. Door were able to roll smoothly. No signs of FOD was found along guide rails & J-rails. Replaced 1501 A3 door actuator. Re-adjust and alignment both door bracket on 1501 A3. Manual door movement found SATIS. Door push/pull test within criteria. Conducted 10/20mm gauge test - passed. Door 30x cyclic test ok, DIR able to extinguish. actuator s/n old:100434 new:89168 N.A/rawi/faizal/zaidi/31.01.23