What was found
(CAN) BLEED AIR OVERHEAT CONDITION (LT HAND) DOWNSTREAM OF ENG BLEED AIR SHUT OFF VALVE. WARNING WAS INTERMITTENT, BUT REMAINED ON. FOLLOWING AFM PROCEDURES, LT ENG WAS SHUT DOWN IN FLIGHT WHEN WARNING PERSISTED AFTER AFFECTED BLEED VALVE WAS CLOSED. AC WAS DIVERTED DEFECT WAS TROUBLESHOT. AFTER SWAPPING BLEED LEAK CONTROL UNITS, DEFECT APPEARED TO BE RECTIFIED. DEFECT REOCCURRED WHILE AC POWER RED UP IN HANGAR. REVEALED THAT SOURCE OF FALSE INDICATION ORIGINATED IN NR 1 DISPLAY CONTROL UNIT (DCU). INVESTIGATION DID NOT REVEAL PREVIOUS EXAMPLES OF THIS TYPE OF FAILURE. DCU IS DESCRIBED AS A COMPLEX COMPUTER THAT MONITORS VARIOUS SYS AND DISPLAYS FAILURES, FAULTS TO FLIGHT CREW. DCU WAS REPLACE.