See also:

Overview button and guidance screen
*: Press and hold the “PWR·VOL” knob for 3 seconds or more to turn off the screen and restart the navigation system. Do this when the vehicle-mounted device response is extremely slow. ...

Volume setting
You can adjust the voice and ring volume. 1. Touch “Volume”. 2. Change each setting according to the following procedures. 3. When you complete all settings, touch “Save”. Automatic vo ...

Have the malfunction repaired immediately.
After taking the specified steps to correct the suspected problem, check that the warning message and light go off. ...