I recently bought a used subaru sti with an avic F700BT already installed.  I just installed have my old sub, it's all wired up correctly, but it only bumps when in FM mode, and has no signal when in CD mode.   I figure it has to be software issue b/c it does work for the radio, just not with mp3 playback. Anyone else experience this or have a possible solution?  Please help, thanks Tim.

probably remote... fm = remote on, cd= remote off... Measure the blue white wire in the radio harness....