What was found
AT FL 320, CABIN BEGAN TO FILL WITH SMOKE. DECLARED AN EMERGENCY FOLLOWED QRH, DIVERT. PERFORMED EXTENSIVE T/S IAW AMM 49-90-00, FOUND LINE LOOSE AT APU OIL PRESSURE SENSOR. RESECURED OIL LINE IAW AMM 20-12-01, OPS CHECKED NORMAL IAW AMM 21-20-00, NO ODOR NOTED IN CABIN.