What was found
DURING BOARDING, # 2 ENGINE FIRE INDICATION OCCURRED. FIRE BELL SOUNDED AS WELL. RAN ENGINE FIRE ON GROUND CHECKLIST TO PULLING T-HANDLE. ALL PAX WERE ASKED TO EXIT THE AIRCRAFT. CALL CFR. THEY VERIFIED NO FIRE OR SMOKE ON #2 ENGINE. REMOVED FROM SERVICE. OPENED #2 ENGINE COWLING, NO EVIDENCE OF FIRE. PERFORMED GVI OF #2 ENGINE FIRE LOOP, NO DEFECTS NOTED. PUSHED #2 ENGINE T-HANDLE BACK IN AND DID A #2 ENGINE FIRE TEST, ALL RELATED LIGHTS ILLUMINATED AND CHIME SOUNDED. REF W/O 315434 FOR WORK PERFORMED. REPLACED FIRE PROTECTION PANEL WITH Q400 AMM 26-00-01-000/400-801. OPS CHECK GOOD. NO OTHER DEFECTS NOTED. RETURNED TO SERVICE.