TIMS showed smoke external at rear M1 car. Staff(GCL) checked and confirmed all saloon cars no abnor mality. Rear Train 122 line cleared, nothing abnormality rep orted. ~~~~~ CE: 1549 Reset but fault recurred.  CHECKED #1549 AND OBSERVED SMOKE SENSOR SIGN OF WATER INGRESS. REPLACED SMOKE SENSOR WITH SPARE. PERFORM CHECK OK. #1549 SMOKE SENSOR S/N NEW KSFSD-01, OLD- . HAIRUL/AZHAR 19.09.2022.