problems with VY 06 radio wont turn off when you remove the key

[leise]

im hoping someone might know why the radio in a VY commodore 06 wont turn off when you remove the key & when your driving the radio turns itself off sometimes then stays on when you lock car up & walk away radio still on the only way to turn radio off is by the off switch can anyone help

[jamby08]

is it a after market head unit or original unit??