To check if you’re in valet mode, open your glove compartment and look to the upper right hand corner for the button labeled “valet.” If the red light is illuminated, that means you’re in valet mode. Just push the valet button once, and the red light will go off—meaning that you’re now able to open your trunk.
And, if all else fails, you can always take your Audi in for a diagnostic test at your local dealership. There could be something wrong with your car’s electrical system.