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Overview
The audio unit acts as the processor for all audio functions. You can select the 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 and rear audio status. For vehicles with navigation, additional audio information is available by touching the audio button. (See the Owner's Manual for more details.)
Vehicles with the premium audio system also include HandsFreeLink (HFL), a USB adapter for playing music from USB devices, and XM radio.
The XM receiver, USB adapter control unit, and audio disc changer pass their signals to the audio unit. In addition, they communicate with the audio unit via the GA-Net bus. Any open connections or short in the wiring in the GA-Net bus circuit will cause audio (including the audio accessories) and navigation functions to appear inoperative.
The audio unit has a built-in EEPROM (electrically erasable programmable read-only memory). This memory holds the audio preset data (AM/FM radio frequency, sound settings) even when the battery power is removed.
Speed-Sensitive Volume Compensation (SVC)
The audio system is equipped with speed-sensitive volume compensation (SVC). The audio unit receives the vehicle speed pulse (VSP) from the PCM. The system processes the speed input and increases the audio system volume level as the vehicle speed increases to compensate for the various interior noises that occur 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 audio unit. The SVC comes from the factory with MID set as the default (see the Owner's Manual for more information).