What was found
(CAN) FLT CREW REPORTS ON START UP, THEY HAD A FIRE WARNING FOR THE NR 2 ENG, FIRE LIGHTS, BELLS & FIRE HANDLE LIGHT WERE ON. ENG SECURED BY ENG FIRE. QRC- YSB TOWER NOTIFIED & FIRE TRUCKS WERE CALLED. CREW DISCHARGED BOTH FIRE BOTTLES, NO EVIDENCE OF FIRE. A/C PAX DEPLANED & MAINT CALLED. MAINT INVESTIGATION CONFIRMED NO EVIDENCE OF FIRE. RT ENG FIRE DETECTION SYS PLACED ON MEL & FIRE BOTTLES REPLACED. AIRCRAFT RETURNED TO SERVICE. AT NEXT RON, MAINT FOUND NR 2 ENG UPPER FIRE/OVERHEAT DETECTOR LOOP CONNECTORS CONTAMINATED. CONNECTORS CLEANED PER SWPM. NO FAULTS FOUND. ENG FIRE/OVERHEAT SYSTEM TESTED PER MM. NO FAULTS FOUND. MEL CLEARED AND AIRCRAFT RETURNED TO SERVICE.