well a smart theif wouldnt steal it, it wont work with out it....if you turn power off from your sterio with out the face plate on it should ask for either a preset code or one you change it to, i think any ways...how my kenwood is.
1987 Nissan pick up-wrecked
1984 Ponitiac grand am-sold
1988 Buick lasabre-sold
1987 Nissan 300zx-sold intake/exhaust
2001 Yamaha r6-sold slip on
2004 Yamaha r1-sold full exhaust
1991 Nissan 240sx-torn down,almost built up.
1994 toyota celica-blown up. exhaust
2005 Honda accord-daily.