What was found
THE CREW NOTED A RED LEFT "BLEED AIR LEAK" EICAS MESSAGE FOR AN ENGINE BLEED AIR LEAK. MESSAGE ILLUMINATED AT FLIGHT 350. CREW FOLLOWED THE QRH PROCEDURES TO SHUT THE ENGINE DOWN DUE TO THE "BLEED AIR LEAK" MESSAGE WOULD NOT EXTINGUISH. CREW DID DECLARE AN EMERGENCY WITH AN UNEVENTFUL LANDING. TROUBLESHOOTING CONDUCTED BY MANUFACTURER REVEALED A FAULTY LEFT BLEED AIR LEAK DETECTION CONTROLLER UNIT. UNIT WAS REPLACED. ALL OPERATIONAL CHECKS SATISFACTORY, WORK ACCOMPLISHED UNDER WO SC11021. AIRCRAFT WAS RETURNED TO SERVICE.