Subaru 2009 Impreza Navigation System - Manual (Page 127)

Audio and Visual 127
Listening to the CD
Listening to tunes in random order
It is possible to play back the tunes in the CD in random order.
1
Select (RDM) while playing back a tune.
With "RDM" displayed for FUNCTION on the CD screen, tunes are
played back in random order.
Selecting again (RDM) releases the playback in random
order.