Normal Operation
The audio system is enabled when the key is in the RUN or ACC position. The CDX6 audio unit uses a center imaging amplifier and a subwoofer amplifier to power the center imaging and subwoofer speakers, respectively. The door speakers are powered directly by the audio unit. The navigation audio system uses an audio unit amplifier and a subwoofer amplifier to power the door speakers and the subwoofer speakers, respectively. The DM1 00i unit directly powers the four door speakers. It is not equipped with a subwoofer or center imaging speakers. All audio units have steering wheel controls. The antenna system contains an antenna module that helps reduce interference when using the AM/FM bands.
Principles of Operation - CDX6 and DM1 00i
When the audio unit is powered up, a wake-up signal is sent to the subwoofer, amplifier, and audio unit amplifiers. Audio output signals are then sent continuously to the subwoofer amplifier and audio unit 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 audio unit is linked to the SCP network and 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.
When the audio unit is powered up, a wake-up signal is sent to the subwoofer, amplifier, and audio unit amplifiers. Audio output signals are then sent continuously to the subwoofer amplifier and audio unit 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 navigation audio unit screen by using video circuits (color generation and display synchronization), between the navigation unit and navigation audio unit. When an on-screen menu key is pressed on the navigation 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 audio unit takes place over the CAN circuits. REFER to ELECTRONIC FEATURE for further information about the navigation system.
Refer to RADIO in SYSTEM WIRING DIAGRAMS for schematic and connector information.
Scheme 1
When the ignition is in the ON position and the audio unit is turned on, communication is possible between the diagnostic tool and the audio unit. The diagnostic tool retrieves codes and data.
The audio unit is powered up when the ignition is in the ON or ACC position. The audio unit will provide audio signals to the speakers, subwoofer amplifier, and center imaging or audio amplifier (if equipped), producing sound.
The radio suppression equipment reduces engine ignition and electrical systems interference transmitted through the speakers.
The audio unit directs the audio signals to the speakers through separate positive and negative circuits for each of the four audio channels: LF, RF, LR, RR, subwoofer I and subwoofer II. The signals are then amplified by the center imaging amplifier and sent to both of the center imaging speakers. The audio unit provides internal circuit protection for shorts to ground, shorts to B+ battery or shorts between any output circuits.
The audio unit directs the audio signals to the audio amplifier through separate positive and negative circuits for each of the four audio channels LF, RF, LR, and RR. The signals are then amplified by the audio amplifier and sent to the four door speakers. The audio unit provides internal circuit protection for shorts to ground, shorts to B+ battery or shorts between any output circuits.
The subwoofer speakers are powered from a separate subwoofer amplifier. The clip detection circuit 7-MD19 (YE/RD), carries out two functions: to turn on the subwoofer amplifier, and to indicate to the audio unit when the subwoofer output distortion signal reaches a damaging level. The audio unit then reduces the audio output signal to the subwoofer amplifier.
The subwoofer speakers are powered from a separate subwoofer amplifier. The clip detection circuit, 7-MD19 (YE/RD), carries out two functions: to turn on the subwoofer amplifier, and to indicate to the audio unit when the subwoofer output distortion signal reaches a damaging level. The audio unit then reduces the audio output signal to the subwoofer amplifier.
The steering wheel audio control consists of a specific resistor value for each button function creating a voltage divider. When a button is pressed, a specific voltage is sent to the audio unit. The audio unit uses the reference voltage to determine which input function has been selected. Circuit 8-MD26 (WH/BK) is the reference voltage circuit between the steering wheel audio controls and the audio unit.
The START input circuit 50-MD15 (GY/OG) is sent to the audio unit when the Ignition is turned to the START position. The audio unit then immediately mutes all speaker amplifier outputs and the subwoofer amplifier enable circuit output to eliminate the possibility of speaker pops during engine cranking.