As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON ENGINE SHUTDOWN A CLICKING SOUND WAS HERD UNDER ENGINE COWLING. UPON INVESTIGATION IT WAS NOTICED THAT THE AIR CONDITIONER COMPRESSOR DRIVE PULLEY ALLEN SCREW HAD LOOSENED OFF AND THE DRIVE PULLEY WAS SLIPPING. DRIVE PULLEY, DRIVE PAD ASSY AND BELT WERE REPLACED AND ACFT WAS RETURNED TO SERVICE.