What was found
AIRCRAFT WAS GROUNDED: ON DESCENT AROUND 3000" AND 1.3 PSI CABIN PRESSURE, ODOR EVENT UNUSUAL / SMELL IN COCKPIT AND FORWARD GALLEY. MAINTENANCE FOUND RESIDUAL SOOT AND OIL IN THE APU AIR INTAKE TO BE THE CAUSE OF THE ODOR. MAINTENANCE CLEANED THE APU INTAKE PER TASK CARD 26T31049006 AND ACCOMPLISHED DECONTAMINATION OF THE ENVIRONMENTAL CONTROL SYSTEM PER TASK CARD 26L00021004. MAINTENANCE ACCOMPLISHED A LEAK CHECK OF THE APU AND NO LEAKS WERE NOTED. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO ODORS NOTED.