TIMS showed Fire External Alarm at car Rear DT. Staff(CCK) checked and confirmed no signs of smoke /fire / burning smell on exterior or interior of train. Rear T209 line clear and confirmed no abnormalities. ~~~~~ 3676 TIMS showed Fire External Alarm. Staff(CCK) confirmed no signs of smoke/fire/burning smell on exterior or interior of train. Rear T209 line clear and confirmed no abnormalities. CE : 3676 fire external pre-alarm able to reset. No abnormality. Depot to follow up.  3676 FC: 723. Checked and found no abnormalities. No water ingress at smoke detector and terminal box. Clean dust accumulation at smoke detector and terminal box. Presence of cable gland and gasket at smoke detector cover. Plaseal check - ok. Swap SDR11 from #3676 to #3675 for preventive measure.  Huzzaidi/Haziq/Hairi/Faizal 12.09.2023