I have a 2009 A3 in which I have recently replaced the Chorus head unit with the Concert II+ head unit to enable me to play the MP3 CDs which I burnt for my previous car. Playing MP3 CDs work exactly as expected.

When I purchased the vehicle I also had the combined usb/sd interface installed. However, I have been unable to get the stereo to play MP3s on either format.

As other forums have highlighted that the interface may not support SDHC I have purchased a 4gb SD card but even with a folder containing a single album the stereo does not play the music.

I have also tried adding an m3u playlist but that had no effect.

When I insert the SD card into the interface the head unit shows CD5 as having a CD inserted but then does not play. If I select one of the other CDs it states there is no CD inserted. I get the same behaviour with the usb device. At no point do a get the "READING" message on the head unit which I get when inserting a CD.

Could someone please put me out of my misery as I am sure I am probably doing something stupid!