Radio changes mode randomly

[sdt]

Hey all. I have a 2006 Mini. The radio has started to change modes to CD on and off. I don't ever use the CD player. I use the radio, and aux mode for my iPhone. While playing either, it will switch to CD for no reason. It will stay on CD mode for a few seconds or a few minutes or longer then go back to whatever I was listening to. Has any one else ever had that happen? I'd appreciate any advice (its very annoying!)

thanks

Susan