Audi Q5   Controls   Doors and windows  Central locking system
The indicator lamp on the remote control key lights up when you press the buttons.
The indicator lamp should light up once briefly when you press one of the buttons briefly. The indicator lamp should flash when you press and hold one of the buttons (convenience open/close).
If the indicator lamp does not light up, this means the battery is exhausted and must be replaced Link. In addition, the indicator lamp lights up and the following message appears in the instrument cluster if the battery is exhausted:
Please change key battery