TC reported Smoke External indication atrear M2 car. Staff (AMK) checked and confirmed no sign of s moke on the exterior of the affected car. Rear train T434 di d line clear and confirmed no sign of smoke. ~~~~~ 2511 SMOKE EXTER L.CHECKED TIMS NOFAULT OCCURED.C/O SMOKE EXTER L UNIT FOR PREVENTIVE MEASURES.SECURITY/FUNCTION CHECKED OK.MONITOR FOR 1 HOUR OK.VINCENT/BUDIMAN 20.08.2023