How to Troubleshoot Audi A8 Sound System

Troubleshooting video guide for 2004 to 2009 Audi A8 audio, navigation, display, and sound system

Common Problems

If the display opens but is blank when turning on ignition, this is usually from bad display interface box or display itself.

If there is sound and display is black, then the display is bad.

If there is no sound and display is black, this could be the display interface box located under the glove box.

Audio Compoents


Navigation unit.


Tools Needed

Screw drivers and/or T20 torque set.

Dashboard removal tool.

CD changer keys.

Fiber-optic loop (lollipop).

CD Changer Removal Instructions (other components follow similar procedure)

Insert CD Changer keys under the front panel of the CD changer.

Remove CD Changer by removing screws.

Disconnect the plugs.

Remove CD Changer by removing screws.

Take caps off located in the back of the glove box and remove the screws.

Using the dashboard removal tool, remove the side cover to the right side of the glove box.

Remove the side cover screws.

Remove the screws from under the wood-panel.

Remove the screws from underneath the glove box.

Drop the glove box.

Remove the display interface box.

Disconnect the plugs.

Insert the fiber-optic loop (lollipop) into the disconnected plug.

Turn on the ignition, and test to see of the issue has been resolved.

Useful Tips

The display interface box is a module that sends the video signal to the navigation display unit. This is common for 90% of display issues. New or exchanged modules must be re-coded, unless you the old module is repaired. If new or exchanged modules are not re-coded, then there is usually no audio with the display working.

If any input/ouput components are malfunctioning, then the fiber-optic loop is open, which causes this issue.

Remember to reconnect the modules after you try the other units.