TIMS showed Smoke External at car 3554.Staff(AMK) checked and confirmed no signs of smoke / fire / burning smell on exterior or interior of train. Rear Train 2 21 feedback no signs of smoke on track. TIMS showed Smoke Ex ~~~~~ 3554 TIMS showed Smoke External. Staff(AMK)confirmed no signs of smoke / fire /burning smell on exterior or interior of train. Rear Train 221 feedback no signs of smoke on track. TIMS showed Smoke External Alarm at car 3554. Staff(BGB) checked and confirmed no signs of burning smell on exterior of train. Rear T232 line clear and confirmed no abnormalities. CE : Found 3554-Tims show smoke external. Reset fault cleared. No abnormality found.  3554 FC 721 smoke external. Check external smoke detetor cable gland and plaseal present. Found terminal side no gasket. OPS20 raised for external smoke detector c/o.  Shaun Lau/Justin Kua 45436 BSD: 3554 - To c/o external smoke detector