Principles of Operation

When the audio unit is powered up a wake-up signal is sent to the subwoofer amplifier. Audio output signals are then sent continuously to the subwoofer amplifier. These signals are then amplified and sent to the speakers as a fluctuating AC voltage (thus producing sound from the speakers). A fluctuating AC voltage audio signal is also sent to the remaining speakers, directly from the audio unit, to produce sound. 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 system/audio unit is linked to the SCP network, therefore trouble codes can 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. The audio unit is linked to the audio corporate protocol (ACP) network. The DVD player sends fluctuating AC voltage audio output signals to the audio unit. The audio unit is linked to the audio corporate protocol (ACP) network. These signals are then amplified by the audio unit and sent to the speakers. The navigation unit is responsible for generating the displays shown on the navigation system audio unit screen by using video circuits (color generation and display synchronization), between the navigation unit the navigation system audio unit. When an on-screen menu key is pressed on the navigation system audio unit screen 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 which key was pressed. Diagnostic communication between the navigation unit and the navigation system audio unit takes place over the CAN circuits. REFER to ELECTRONIC FEATURES for further information about the navigation system. The navigation system audio unit has voice command features that are activated through the voice button on the steering wheel control switch. The microphone is integrated in the interior rear view mirror.