System Operation

WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

System Diagram

Courtesy of FORD MOTOR COMPANY

Network Message Chart

NOTE: A missing network message is indicated by a U-code DTC. When a missing message DTC (U-code) sets, it is important to look for symptoms present in the audio system and throughout the vehicle, and to review the complete message list to determine which other modules rely on the same message. Refer to CAN Module Communication Message Chart in Module Communications Network . When the other modules have been identified, run the self-test for those modules. If the same message is missing from those modules, the identical, or similar lost communication DTCs may be set in those modules. Confirmation of missing messages common to multiple modules can indicate that the originating module is the source of the concern, or that the communication network may be at fault.

It is very important to understand the following:

Where the input originates
All of the information necessary for a feature to operate
Which module(s) receive(s) the input or command message
Which module controls the output of the feature
If the module that receives the input controls the output of the feature, or whether it outputs a message over the CAN to another module.

Module Network Input Messages - ACM

Broadcast Message	Originating Module	Message Purpose
Audio settings	IPC	Used to set the audio system listening source from the steering wheel switch, through the IPC infotainment display.
Battery low state of charge	BCM	Used to disable the functionality of the ACM when the load shedding feature is active.
Beltminder warning status	IPC	Used to mute speaker output so the Belt-Minder ® tone can be more easily heard. The speaker output is muted until the safety belt(s) are buckled. This message only applies to vehicles with a MyKey ® that is enabled and in use.
Car mode	BCM	Used to disable certain audio system features when the vehicle is in transport or factory mode.
Day/night status	BCM	Used to adjust the AM radio reception sensitivity.
Ignition status	BCM	Used to indicate the ignition state (OFF, ACCESSORY, RUN and START) required to support the audio system operating modes and fault reporting.
Steering wheel switch multimedia commands	SCCM	Used to control the audio system from the RH steering wheel switches.
Steering wheel switch volume command	SCCM	Used to set the audio system volume from the RH steering wheel switches.
Rear audio commands	Audio RCU module	Used to set the audio system volume, select media and utilize the seek +/- function from the rear seat audio controls.

Module Network Input Messages - Audio RCU Module

Broadcast Message	Originating Module	Message Purpose
Ignition status	BCM	Used to indicate the ignition state (OFF, ACCESSORY, RUN and START) required to support the audio system operating modes and fault reporting.
ACM information and status	ACM	Used to display the current audio system media selection at the rear seat audio controls.

Module Network Input Messages - APIM

Broadcast Message	Originating Module	Message Purpose
ACM signals	ACM	Used to display the ACM radio functions such as seek, tune and AM/FM stations on the FDIM.
Airbag deployment status	RCM	Used to monitor airbag deployment status for 911 assist.
Audio source	ACM	Used to monitor the current audio system media source selection.
DSP volume status	Audio DSP module	Used to display the audio DSP module volume on the FDIM.
CD changer status	ACM	Used to display the loaded or ejected CD status on the FDIM
Door ajar status	BCM	Used to determine the door status to support the accessory delay feature.
Car mode	BCM	Used to disable certain audio system features when the vehicle is in transport or factory mode.
FCIM button press data	FCIM	Used to control the APIM media sources and interact with connected devices from the FCIM.
Gear lever position	PCM	Used to provide transmission gear selection for the navigation feature.
Ignition key type	BCM	Used to determine if a MyKey ® is enabled and in use.
Ignition status	BCM	Used to indicate the ignition state (OFF, ACCESSORY, RUN, and START) required for APIM operating modes and fault reporting.
Language selection	IPC	Used to display information on the FDIM in the selected language.
Navigation rolling wheel count	ABS module	Used to provide dead-reconing vehicle position tracking when the GPS signal is temporarily unavailable.
Steering wheel switch multimedia commands	SCCM	Used to control the audio system from the RH steering wheel switches.

Module Network Input Messages - Audio DSP Module

Broadcast Message	Originating Module	Message Purpose
Belt-Minder ® audio mute	IPC	Used to mute speaker output so the Belt-Minder ® tone can be more easily heard. This message only applies to vehicles with a MyKey ® enabled and in use. The audio system is muted until the safety belt(s) are buckled.
FCIM set volume	FCIM	Used to set the audio system volume from the FCIM.
Ignition status	BCM	Used to indicate the ignition state (OFF, ACCESSORY, RUN, and START) required for audio DSP module operating modes and fault reporting.
MyKey ® volume limit	IPC	Used to limit the maximum audio system volume when a MyKey ® restricted key is in use.
Navigation audio settings	APIM	Used to set the navigation command volume.
Vehicle speed	PCM	Used to support the speed compensated volume feature.

Module Network Input Messages - FCIM

Broadcast Message	Originating Module	Message Purpose
Car mode	BCM	Used to disable certain audio system features when the vehicle is in transport or factory mode.
Door ajar status	BCM	Used to determine the door ajar status for the accessory delay feature.
Day/night status	BCM	Used to set the day/night illumination status of the FCIM.
Ignition status	BCM	Used to indicate the ignition state (OFF, ACCESSORY, RUN, and START) required for FCIM operating modes and fault reporting.

Accessory Delay Feature

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.

AM/FM Radio

The AM/FM antenna receives radio waves and sends them to the antenna isolator module. The antenna isolator module amplifies the signals and sends them through the AM/FM antenna coaxial cable to the ACM. The radio waves are converted into fluctuating AC voltage by the ACM and sent as left and right analog audio signals to the audio DSP module.

Android Auto™

Android Auto™ integrates select Android device features with the vehicle audio system controls and touchscreen. The Android Auto™ interface displays phone information cards on the touchscreen and provides control of Google Play Music, Google Maps, and other compatible apps.

The Android Auto™ interface is available on the touchscreen when a device running Android 5.0 (Lollipop) or later is connected to a vehicle USB port. To use Android Auto™, the Android Auto™ app must be installed on the owner's device.

For more information, refer to Android Auto™ in the Owner's Literature.

Apple CarPlay™ - If Equipped

Apple CarPlay™ integrates select iPhone features with the vehicle audio system controls and touchscreen. The Apple CarPlay™ interface provides direct access and control of Music playlists, Apple Maps directions, iMessages, Siri, and phone calls. In addition, compatible iOS apps can also be controlled via the Apple CarPlay™ interface.

The Apple CarPlay™ interface is available on the touchscreen when an iPhone 5 or later running iOS 7.1 or later is connected to a vehicle USB port using an Apple Certified Lightning cable. To use Apple CarPlay™, Siri must be enabled on the owner's iPhone.

For more information, refer to Apple CarPlay™ in the Owner's Literature.

APIM Programming

The APIM requires specific programming procedures for correct operation when the module is replaced, when upgrades are available and requested, or when directed by a TSB, Field Service Action (FSA), Special Service Message (SSM), or Electronic Field Communication (EFC) to resolve SYNC ® performance concerns.

Audio Extended Play

This feature allows the audio system to operate with the ignition OFF, regardless of door latch position. When the power button on the FCIM is pressed, audio system functionality is enabled and remains active for a period of 20-60 minutes, depending on configuration settings. To turn the audio system off, the press the power button on the FCIM. Audio extended play will not function if the battery load shed is active.

Battery Load Shed

The BCM uses the battery current sensor to monitor the battery state of charge. The battery current sensor is attached to the battery ground cable. With the ignition in RUN, ACC, or OFF, a load shed message is sent over the CAN when the BCM determines that the battery state of charge is below 40%, 45 minutes have elapsed, or 10% of the charge has been drained. This message turns off the audio system to save the remaining battery charge. Under this condition, "Battery Saver - System Off" is displayed on the centerstack infotainment display to notify the driver that battery protection actions are active. To clear the load shed state, start the vehicle.

Bluetooth Mode

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 9.75 m (32 feet).

The Bluetooth interface can accommodate both Bluetooth-enabled mobile phones and Bluetooth-enabled media devices. The SYNC ® system allows interaction with several types of customer Bluetooth devices, including mobile phones and media devices. The APIM contains an on-board Bluetooth chipset, which enables certain wireless devices to interact with the system. Any Bluetooth device used with the SYNC ® system must first be paired with the system before it is operational.

Any Bluetooth device used with the SYNC ® system must first be paired with the APIM on-board Bluetooth chipset before it can become operational. Pairing a Bluetooth device is accomplished through the "Add Device" selection of the phone menu. When pairing a device, the SYNC ® system generates a unique PIN that must be entered on the Bluetooth device in order for the pairing process to be successful. There are also some device-specific actions that must take place. For information on the pairing process, refer to the Owner's Literature.

Multiple Bluetooth phones and Bluetooth media devices can be paired to the APIM at the same time. The APIM supports an active connection with one Bluetooth phone and one Bluetooth media device at a time. If an additional device of either type is paired and made active, the APIM ends any active connection with an already-paired device, and establishes an active connection with the new device.

It is important to understand that while most Bluetooth devices can pair with the SYNC ® system, not all Bluetooth devices have the same level of features available when interacting with the SYNC ® system. To determine if a Bluetooth device is supported, verify the customer's device is on the compatibility list for the current APIM software level. For a list of compatible phones, refer to the http://owner.lincoln.com/how-tos/sync-technology/all/phone-setup/phones-compatible-with-sync.html .

Chimes

Various vehicle systems send chime requests over the CAN to the IPC. The following are determined as the IPC processes these requests:

Chime characteristics such as tone, tone length, number of repetitions, and time between tones
Chime output volume
Priority of the chime request
Which speakers (all, front, or rear) will play the specific chime

The IPC sends the processed requests over the CAN to the ACM. The ACM outputs the left and right analog chime tones to the audio DSP module over dedicated chimes circuits as fluctuating AC voltage. The audio DSP module outputs the chime tones to the appropriate audio system speakers as fluctuating AC voltage.

For more information, Instrumentation, Message Center, and Warning Chimes .

Compass

The GPS antenna, integral to the satellite antenna, is used to acquire the compass heading. The compass heading is sent through the GPS /satellite radio coaxial cable, GPS /satellite radio splitter, and GPS coaxial cable to the APIM. The APIM uses this data in addition to wheel speed and wheel rotation direction CAN messages from the ABS module to calculate and provide accurate vehicle tracking. The APIM processes the data and transmits it though the LVDS (Low Voltage Differential Signaling) cable to be displayed on the FDIM. In the event that the GPS fix or signal is temporarily lost, the APIM will continue to use the CAN messages from the ABS module as well as information from the internal gyroscope and accelerometer to provide accurate vehicle tracking.

DSP

The Sony ® audio system provides theater quality sound in the vehicle. Audio signals are sent from the ACM and APIM to the audio DSP module. The audio DSP module processes the audio signals and sends them to the speakers.

The audio DSP module determines the correct audio environment based on the audio signals and network messages it receives from other audio system modules. These messages include information such as fade/balance and speed compensated volume settings.

HD Radio ® - If Equipped

HD Radio ® is a subscription-free service.

HD Radio ® technology allows an AM or FM radio station to duplicate their traditional analog channel with a matching digital channel. Some FM radio stations subdivide the digital output signal into multiple channels that are not duplicates of the analog channel. These extra multicast channels vary in availability and are called HD2, HD3 and HD4 channels.

The AM/FM antenna receives radio waves containing data (station call letters, artist names, song titles, etc.) and digital HD Radio ® audio. The radio waves are sent through the AM/FM antenna coaxial cable to the HD Radio ® receiver built into the ACM. The data is sent to be displayed on the centerstack infotainment display, and the audio is converted into fluctuating AC voltage and sent as left and right analog audio signals to the audio DSP module. The audio DSP module processes the audio signals and sends them to the speakers as fluctuating AC voltage.

MyKey ® Audio Operation

The following MyKey ® features are always enabled when a MyKey ® is in use, and are not configurable on/off with an administrator key:
- Belt-Minder ®: The audio system is muted, and "BUCKLE UP TO UNMUTE AUDIO" is displayed in the FDIM until the safety belts are buckled.
- Satellite Radio: Adult content stations are blocked by being muted.
The following MyKey ® features are configurable with an administrator key:
- 911 Assist™: If the administrator has selected "Always on" in the MyKey ® menu, 911 Assist™ is enabled and cannot be disabled.
- Do Not Disturb: If the administrator has selected "Always On" in the MyKey ® menu, the Do Not Disturb feature is enabled and cannot be disabled.
- Speed Compensated Volume: If the administrator has enabled the Volume Limiter feature, the speed compensated volume feature will be disabled.
- Speed Limiter: If the administrator has enabled the Speed Limiter feature, the audio volume level is temporarily reduced so the top speed alert chime can be heard when the preselected top vehicle speed is reached.
- Speed Minder: If the administrator has enabled the Speed Minder feature, the audio volume level is temporarily reduced so the speed alert chime can be heard when the preselected Speed Minder vehicle speed is exceeded.
- Volume Limiter: If the administrator has enabled the Volume Limiter feature, the audio system volume is limited to 45%. During an attempt to exceed the limited volume, "MyKey ® VOLUME LIMITED" is displayed in the information display.

Refer to the Owner's Literature for more information on MyKey ®.

Navigation - If Equipped

The navigation system guides the user to a pre-entered destination.

The navigation display is shown on the FDIM.

Map data is stored in the APIM. The GPS antenna, integral to the satellite antenna, receives GPS data and sends it through the GPS /satellite radio coaxial cable, GPS /satellite radio splitter, and GPS coaxial cable to the APIM. The APIM uses this GPS data in addition to wheel speed and wheel rotation direction CAN messages from the ABS module to calculate route information and provide accurate navigation tracking. In the event that the GPS fix or signal is temporarily lost, the APIM will continue to use the CAN messages from the ABS module as well as information from the internal gyroscope and accelerometer to provide accurate vehicle tracking.

The voice recognition system allows the user to interface with the navigation system without using the FDIM. A microphone located in the headliner provides a direct input to the APIM.

For more information, refer to Navigation in the Owner's Literature.

RDS

RDS allows metadata (information such as station call letters, artist, song title, and genre) to be contained within FM radio waves. If the RDS feature is turned on, a PTY (Program Type) can be chosen. Once the customer has chosen a single PTY such as Sports, Rock, Religious Music, or Weather, the SEEK or SCAN button is pressed, and the ACM only tunes channels within the selected category. If a channel within the selected category is not found, the ACM continuously seeks or scans.

Rear Seat Audio Controls

The audio RCU module allows rear seat occupants to control the audio systems volume, select the media input, display the radio station, display SIRIUS ® radio channel, CD track and clock. The rear seat audio controls are integral to the audio RCU module. The rear seat audio control requests are sent from the audio RCU module to the ACM over the I-CAN.

Satellite Radio

Satellite radio is a subscription-based service. When a satellite radio subscription is activated, the ESN of the satellite radio receiver built into the ACM is associated with the VIN.

The roof-mounted satellite antenna receives Satellite Digital Audio Radio Service (SDARS) signals containing metadata (station call letters, artist names, song titles, etc.) and digital satellite radio audio. These signals are sent through the GPS /satellite radio coaxial cable, GPS /satellite radio splitter, and satellite radio coaxial cable to the satellite radio receiver built into the ACM. The metadata is separated from the audio by the ACM. The metadata is sent to the APIM to be displayed on the FDIM, and the audio is converted into fluctuating AC voltage and sent as left and right analog audio signals to the audio DSP module. The audio DSP module processes the audio signals and sends them to the speakers as fluctuating AC voltage.

SIRIUS Travel Link - If Equipped

SIRIUS Travel Link is a subscription-based service and requires a separate subscription from the satellite radio. When a SIRIUS Travel Link subscription is activated, the ESN of the satellite receiver built into the ACM is associated with the VIN and registered in the SIRIUS database.

SIRIUS Travel Link allows the customer to receive information for:

Fuel Prices
Movie listings (theaters, movie titles, ratings, start and run times)
Ski Conditions (resorts, lodging, conditions)
Sports (in-game and final scores, weekly schedules, headlines)
Traffic (traffic flow, accidents, construction, road closings)
Weather (current weather, forecasts, radar images)

The SIRIUS Travel Link feature requires the use of an APIM equipped with navigation.

The roof-mounted satellite antenna receives satellite signals containing SIRIUS Travel Link data. The rate that the antenna receives the signals for each category to update the data depends on the category. These signals are sent through the satellite radio antenna coaxial cable to the satellite radio receiver built into the ACM. The ACM sends the data to the APIM through the SDL (sirius data link) circuits, and then to the FDIM to be displayed.

For more information, refer to Sirius Travel Link in the Owner's Literature.

Speed Compensated Volume

The audio DSP module adjusts the audio system volume based on the vehicle speed message received from the PCM to compensate for road and wind noise.

When a MyKey ® is in use and the MyKey ® radio volume limiter is enabled, the speed compensated volume is disabled.

Steering Wheel Switch Functions

The RH steering wheel switches operate the seek +/-, volume +/-, and the audio system SYNC ® functions.

The SCCM sends a 5-volt reference voltage to the RH steering wheel switch on the input circuits. When a switch is pressed, the voltage is routed through the corresponding resistor(s) within the switch, and then to ground through the SCCM. The SCCM monitors the resultant voltage drop to determine which switch was pressed. The voltage drop varies depending upon the resistance of the specific switch pressed.

The SCCM sends a CAN network message to the APIM for the SYNC ® switches and to the ACM for the redundant audio controls.

SYNC ® AppLink™

SYNC ® AppLink™ allows applications installed on the customer's device to be controlled using the steering wheel switches, FCIM, and/or FDIM.

All devices must be paired with the SYNC ® system via Bluetooth, and Apple ® devices must also be connected to a vehicle USB port.

Data is transmitted back and forth between the customer's device and the APIM through Bluetooth, or through the USB port for Apple ® devices.

For more information, refer to Apps and AppLink in the Owner's Literature.

SYNC ® System

The SYNC ® system uses, Bluetooth, USB, FDIM, GPS, microphone, and CAN messages as inputs to the APIM to control the entertainment system, phone, climate control system, ambient lighting system (if equipped), and navigation system (if equipped).

The SYNC ® system provides the ability to:

Control the entertainment system, climate control system, ambient lighting system, navigation system (if equipped), and several other vehicle systems using the touchscreen or voice controls
Send and receive phone calls via a paired Bluetooth-enabled phone
Send and receive text messages via a paired Bluetooth-enabled phone
Connect media devices (such as an iPod ® or USB device) to play audio files through the audio system speakers
Initiate an emergency assistance call (911 Assist™) when the airbags deploy

All SYNC ® system features are not available with every phone/device. To determine if the APIM supports a particular phone, tablet, or media player, or feature of one of those devices, review the device compatibility list. Refer to the http://owner.lincoln.com/how-tos/sync-technology/all/phone-setup/phones-compatible-with-sync.html .

The customer can update the CIP by using a USB flash drive or a Wi-Fi connection not requiring a browser sign in or two-step security validation. The update is approximately 600 MB.

If the APIM is connected to a stationary Wi-Fi network (such as a home or restaurant) for automatic updates, the update download occurs when the ignition is OFF. To limit battery drain, the APIM is allowed to download the update for up to 150 minutes in a month for a maximum of 30 minutes at a time.
If the APIM is connected to a mobile Wi-Fi hotspot (network) for automatic updates, the update download can occur with the ignition in ON/RUN and the vehicle stationary or in motion.

Once the update download and installation is complete, an ignition cycle must occur before the update becomes active. For more information, refer to "Updating Your System" in the Owner's Literature.

For more information on the SYNC ® system, refer to SYNC in the Owner's Literature.

USB Mode

When a portable media device, such as an iPod ®, with its available cable, or portable mass storage such as a USB thumb drive, is connected to a vehicle USB port, audio from the device can be played through the vehicle speakers. Functions such as volume, seek, fast forward, pause, etc. can be controlled by the vehicle audio controls.

When playing media files stored on a mass storage device such as a flash drive, the SYNC ® system only plays files that do not have DRM protection.

In addition to audio information (track length, track number, etc.), metadata (information such as artist, album title, song title, and genre) may also be sent to the APIM from a device connected to the vehicle USB port. The APIM uses the metadata to create indexes that can be used to sort for particular music based on the customer's preferences. Not all USB devices can send metadata to the APIM. When a new media device is connected to the SYNC ® system, the APIM automatically indexes the information. This may take 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. This reduces the time needed to index the device.

Voice Recognition

Voice recognition allows phone, navigation system (if equipped), audio system, and climate control system functions to be controlled with voice commands. This minimizes driver distraction by reducing or eliminating the need to interact with the centerstack infotainment display and/or device while driving.

When the voice steering wheel switch is pressed, an audible prompt originating at the APIM is heard from the speakers. Based on the customer's setting, audible prompts will either be a voice or a simple tone. When interaction mode is set to standard, detailed voice guidance is provided. When interaction mode is set to advanced, most prompts are tones only, and minimal voice guidance is provided. The microphone receives the voice commands and sends them to the APIM.

For more information, refer to Voice Recognition in the Owner's Literature.