Principles of Operation

PRINCIPLES OF OPERATION

Standard Audio
When the audio unit is powered up, audio output signals are sent continuously to the speakers as a fluctuating AC voltage, thus producing sound from the speakers. The steering wheel controls are a multiplexed system that use different resistor values to produce different voltage levels on a single circuit. Each button that is pressed results in a unique voltage signal at the audio unit. This voltage signal is then interpreted by the audio unit as a distinct command. The audio unit is linked to the standard corporate protocol (SCP) network, allowing trouble codes to be obtained with a diagnostic tool. The audio unit also has a self-diagnostic mode that can be entered by pressing preset buttons 3 and 6 simultaneously.

Navigation Audio Unit
When the audio unit is powered up, a wake-up signal is sent to the amplifier. Audio output signals are then sent continuously to the amplifier. These signals are then amplified and sent to the speakers as a fluctuating AC voltage, thus producing sound from the speakers. The steering wheel controls are a multiplexed system that use different resistor values to produce different voltage levels on a single circuit. Each button that is pressed results in a unique voltage signal at the audio unit. This voltage signal is then interpreted by the audio unit as a distinct command.

The navigation unit is responsible for generating the displays shown on the video screen display by using video circuits (color generation and display synchronization), between the navigation unit and video screen. When an on-screen menu key is pressed on the video screen display a signal is sent to the navigation unit through the controller area network (CAN) circuits. Refreshed data is then sent through the video circuits, and a new screen is displayed corresponding to the key that was pressed. Diagnostic communication between the navigation unit and the video screen display takes place over the CAN circuits.

Rear Auxiliary Audio Controls
The rear auxiliary audio controls (if equipped) allow control of certain audio functions by the rear seat passengers. The rear auxiliary controls are located on the top rear of the center console. The signals are sent to the rear audio/climate control module, which sends the signals to the audio unit through the audio corporate protocol (ACP) network.