The Audio Unit acts as the ‘‘processor'' for all audio functions. Select audio functions from the front panel, the audio remote (on the steering wheel), or by using the navigation voice control system. The audio display provides the current front audio status. For vehicles with the navigation option, additional audio information is available by touching the audio button on the Navigation Audio Screen (See the owner's manual and the navigation system manual for more details.)

The navigation unit pass their signals to the audio unit. In addition they communicates with the audio unit via the GA-Net bus. Any open connection in the GA-Net bus circuit will cause audio and navigation functions to appear inoperative.

A Security signal is daisy-chained between the audio, and navigation components for integration into the vehicle's alarm system.

Some audio systems are equipped with speed-sensitive volume compensation (SVC). The navigation or audio unit receives the vehicle speed pulse (VSP) from the ECM. The system processes the speed input and increases the navigation or audio system volume level as the vehicle speed increases to compensate for the various interior noise that occurs at higher speeds. When the vehicle slows down, the volume returns to its normal level. The SVC has four settings: SVC OFF, LOW, MID and HIGH that can be adjusted using the navigation or audio unit. The SVC comes from the factory with the MID set as the default.

To change the audio unit SVC setting, press the ‘‘tune folder sound'' knob repeatedly until the SVC is displayed, rotate the knob to adjust the SVC to the desired setting (SVC, OFF, LOW, MID or HIGH)

To change the navigation unit SVC setting, press the AUDIO button, and then select the SOUND icon on the navigation display. Press the navigation display to select the desired setting (OFF, LOW, MID, HIGH).

The optional navigation system provides voice control audio, and CD player. Voice control commands communicated on the GA-Net (audio unit). When using the talk/back button, the audio is muted on all speakers and you get navigation sound on the front channels. When using the navigation/route guidance (RG/HFT), the front speakers give the telephone sound and the navigation sound and the rear speakers continue to play. For more information, see the navigation section. The outline of the interruption function is shown in this table.

Contents	Audio output
	Left front CH	Right front CH	Right rear CH	Left rear CH
Talk/back Buttons	Navigation voice output	Navigation voice output	Muted	Muted
Route guidance	Navigation voice output	Navigation voice output	Audio	Audio
HFT	Telephone voice output	Telephone voice output	Audio	Audio