Principles Of Operation

Information and Entertainment System

Principles of Operation

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

Audio Control Module (ACM)

The Audio Control Module (ACM) can be operated with the ignition in RUN or ACC. The accessory delay feature allows the audio system to be operated for a preset period of time after the ignition is turned off and a front door has not been opened. The ACM sends AC voltage audio signals to the speakers or to the amplifier, depending on vehicle configuration. The ACM can produce its own DTCs, which can be communicated to the scan tool through the Medium Speed Controller Area Network (MS-CAN).

Front Controls Interface Module (FCIM)

The Front Controls Interface Module (FCIM) acts as a customer interface with the audio system. The FCIM sends messages over the MS-CAN when any button is pressed.

Vehicles with navigation are not equipped with an FCIM.

Front Display Interface Module (FDIM)

For vehicles without navigation, the Front Display Interface Module (FDIM) is a stand-alone module. It receives messages for all of its displays, which include:

- Audio information
- Climate control fan speed and temperature setting
- Outside air temperature (if equipped)
- Compass heading (if equipped)

For vehicles with navigation, the FDIM does not display audio system, navigation, or compass heading information.

Satellite Audio

The satellite audio system consists of a Satellite Digital Audio Receiver System (SDARS) module, a satellite radio antenna, and a satellite radio antenna cable. For early build vehicles without navigation, an external SDARS module is utilized. For late build vehicles and all vehicles with navigation, the SDARS module is built-in to the ACM. The satellite radio antenna receives digital audio signals and sends them to the SDARS module (early build vehicles without navigation) or to the ACM (all except early build vehicles without navigation).

Subwoofer

The Audiophile subwoofer and amplifier are integral. The enable/clip detection circuit carries out 2 functions: to turn the amplifier on, and to indicate to the ACM when the subwoofer output distortion signal reaches a damaging level. The ACM then clips the audio output signal to prevent damage to the subwoofer.

Navigation System

The vehicle navigation system guides the user to a pre-entered destination. No navigation map DVD is needed, as the map guidance information is stored in the ACM. The ACM calculates route information based on Global Positioning System (GPS) data. The GPS antenna tracks several satellites simultaneously. The ACM also uses vehicle speed and transmission gear selected signals received through the MS-CAN to detect vehicle speed and direction, resulting in more accurate navigation tracking.

The navigation display is part of the ACM. Either the touchscreen or the buttons on the ACM can be used to interact with the navigation system.

The compass heading is derived from the GPS antenna signal. There are no serviceable parts for the compass.

A voice recognition system allows the user to interface with the system without using the touchscreen. A microphone located in the interior rear view mirror provides a direct input to the ACM. The microphone is shared with the SYNC system, if equipped.

Jukebox Feature

The navigation ACM contains a 10 gigabyte on-board hard drive that is capable of storing music ripped (recorded) from a music disc. The music can be loaded into the jukebox by inserting a disc (in the correct format) and following the on-screen instructions to load the music into the ACM. The jukebox can not rip MP3 discs.

SYNC System

The SYNC system allows interaction with several types of customer devices, including mobile phones and media devices. The system is comprised of the Accessory Protocol Interface Module (APIM), a microphone (located in the interior rear view mirror), the Universal Serial Bus (USB) cable and port, and the audio input jack. The APIM contains an on-board Bluetooth chipset, which enables certain wireless devices to interact with the system.

The APIM consists of 2 internal modules: the Consumer Interface Processor (CIP) and the Vehicle Interface Processor (VIP). The modules are not replaceable individually, but can be flashed independently, if required.

The CIP interfaces with all of the inputs to the APIM. It contains an analog-to-digital-to-analog converter, as well as the Bluetooth chipset. Any consumer-available application upgrades that are available are loaded directly to the CIP through the USB port.

The VIP provides an interface between the CIP and the vehicle. Its main functions are controlling the APIM power management and translating both inbound and outbound signals over the Controller Area Network (CAN). In addition, the VIP interrogates the modules on the network to retrieve any DTCs when a vehicle health report is requested.

The APIM can receive inputs from the following audio sources:

- USB port
- Audio input jack
- Bluetooth

The USB port can be used for connecting a media device (such as an iPod(R)) with the device's available cable, or for directly plugging in a portable mass storage device (such as a "thumb drive"). When playing media files stored on a mass storage device, the SYNC system will only play files that do not have Digital Rights Management (DRM) protection. The USB port can also be used for uploading vehicle application upgrades.

The USB port is powered by the APIM, so no external power source is needed to power a device plugged into the USB port if the device supports this feature.

The audio input jack can be used for connecting a media device (such as an iPod(R)) utilizing a 1/8-inch audio jack. When a device is connected through the audio input jack, only the speaker volume can be controlled by the ACM. All other functions (such as seek, fast forward, pause, etc.) must be carried out on the device itself.

The Bluetooth interface can accommodate both Bluetooth-enabled mobile phones and Bluetooth-enabled media devices. Any Bluetooth device used with the SYNC system must first be paired with the system before it is operational.

Bluetooth is a secure, short-range radio frequency that allows devices to communicate wirelessly through radio waves. The operating range of a Bluetooth signal is a maximum of 32 feet.

Only one Bluetooth phone and one Bluetooth media device can be connected to the system at any one time. If an additional device of either type is paired with the system and made active, the APIM will disconnect any active connection and establish a connection with the new device.

It is important to understand that not all mobile phones have the same level of features when interacting with the SYNC system. For a list of compatible phones, refer to the SyncMyRide website .

In addition to audio information, metadata may also be sent to the APIM from a device plugged into the USB port. Metadata consists of such information as artist, album title, song title, and genre. The metadata is used by the APIM to create indexes that can be used to sort for particular music, based on customer preference. Not all USB devices will send metadata to the APIM; also, no metadata is transferred when a device is connected through the audio input jack. When a new media device is connected to the SYNC system, the APIM will automatically index the information. This can take up to several minutes (depending on the amount of data on the device), and is considered normal operation. When a device that was previously connected to the SYNC system is reconnected, the APIM updates the index (rather than creating a new one), which reduces the amount of time needed index the device.

The APIM receives both stereo and mono sound inputs, and can also transmit both stereo and mono sound. The mono function is used to receive the microphone input. It is also used to send sound to the ACM for voice prompts, the Text-To-Speech (TTS) feature, ring tones, and any audio received through a connected mobile phone. The TTS feature speaks information so that it does not have to be read from the display.

The APIM communicates on the MS-CAN and High Speed Controller Area Network (HS-CAN). Communication with the scan tool is established through the HS-CAN.

Voice Recognition For Vehicles With Navigation And The SYNC System

When the audio system enters voice recognition mode, the ACM initially controls the voice recognition feature. The microphone is wired directly to the APIM, which relays the microphone input to the ACM through dedicated wiring. If the first command spoken is part of the ACM voice recognition set, the ACM retains control of the voice recognition and takes the appropriate action(s). If the first command spoken is part of the APIM voice recognition set, the ACM shuts off its own voice recognition and broadcasts a Controller Area Network (CAN) message to the APIM, transferring the voice recognition to the SYNC system and providing the voice command that was spoken. The ACM controls the voice engine for the base audio, navigation, and climate control systems. The APIM controls the voice engine for the SYNC system (USB port, audio input jack, Bluetooth).

AM/FM Antenna

A co-axial antenna cable connects the antenna to the ACM. If the vehicle is satellite radio-ready, a combination AM/FM/satellite radio antenna is utilized. The roof-mounted satellite radio antenna receives digital audio signals and transfers them to the SDARS module (vehicles without navigation) or the ACM (vehicles with navigation) through the satellite radio antenna cable.

Global Positioning System (GPS) Antenna

For vehicles equipped with navigation, the GPS antenna receives information from satellites. The compass heading is also derived from the GPS signal. A combination GPS/satellite radio is utilized.

Steering Wheel Controls

The steering wheel controls consist of a series of resistors. Each steering wheel control switch function corresponds with a specific resistance value within the switch. When a switch is pressed, the ACM (or the APIM) monitors the change in reference voltage to determine the requested function.

Audio Input Jack

The audio input jack allows for a portable MP3 player to be connected to the vehicle audio system. When a portable MP3 player is connected, audio from the MP3 player can be played through the vehicle speakers.

Noise Suppression Equipment

The radio frequency suppression equipment reduces interference transmitted through the speakers by the engine ignition and electrical systems. When installing any new radio suppression equipment components, make sure that a good contact is made at all connections.

Audio Signals

Stereo signals contain left and right channel information, and are used for most audio signals, including:

- ACM-to-speaker output
- ACM-to-subwoofer amplifier output (Audiophile only)
- Subwoofer amplifier-to-speaker output
- SDARS module-to-ACM output (vehicles without navigation)
- APIM-to-ACM media output

A mono signal is used for the microphone input to the APIM. The mono signal is also used for the voice prompts, the Text-To-Speech (TTS) feature, ring tones, and any audio received through a connected mobile phone. These audio signals are output from the APIM to the ACM. The mono and stereo outputs from the APIM utilize separate circuits from the stereo output.

A digital signal is used to transmit data from a media device connected through the USB port to the APIM. The APIM then converts the signal to analog and relays the signal to the ACM.

A wireless signal is used to broadcast audio signals from a Bluetooth media device to the APIM, which converts the wireless audio signal to analog and relays it to the ACM.

Network Communication

The following audio system components communicate via the MS-CAN:

- ACM
- Navigation ACM
- SDARS module
- FDIM
- FCIM

There are numerous messages internal to the audio system. The functions of these messages include (but are not limited to):

- Changing the audio source
- Changing equalizer settings
- Updating the FDIM display
- Dialing phone numbers from the FCIM (if equipped with the SYNC system)

In addition, the following messages are utilized by the audio system in conjunction with systems outside of the audio system: