As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DESCENT WITH THRUST LEVERS AT IDLE STRANGE SMELL PERMEATED COCKPIT. REFERENCE PREVIOUS WRITE UP. RAN ENGINES AT TAKEOFF PWR FOR 5 MINS WITH BOTH PACKS OPERATING. ALSO RAN EACH ENGINE INDIVIDUALLY AT TAKEOFF WITH CORRESPONDING PACK OPERATING. NO SMELL NOTED. RAN EACH ENGINE IN REVERSE THRUST. NO SMELL NOTED. CANNOT DUPLICATE PROBLEM.