Network Communication

WARNING: This page is about a different car, the 2011 Lincoln MKT. However, it is still accessible from the selected car via links, so may be relevant.

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

ACM
Audio DSP module
FCIM
RETM
APIM

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 or FDIM

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

AUDIO SYSTEM MESSAGE LIST

Message	Transmitting Module	Receiving Module(s)	Audio System Function
Accessory Delay Status	SJB	ACM FCIM RETM	When active, this signal allows the audio component to be operated after the vehicle is shut off.
Average Fuel Economy Data	IPC	ACM	Provides average fuel economy data to the ACM.
Belt-Minder® Status	IPC	ACM	When this message is active, the speaker output is reduced to allow the Belt-Minder® tone to be more easily heard. This message only applies to vehicles with MyKey™ that have this feature currently enabled.
Compass Display Status	IPC	FDIM	Indicates the compass heading or mode (calibration, zone).
eCall Notification	Restraints Control Module (RCM)	APIM	Provides the eCall status to the APIM. This message is also used to confirm that the APIM and the RCM are both configured for the eCall feature.
eCall Status	APIM	RCM	Provides the eCall status to the RCM. This message is also used to confirm that the APIM and the RCM are both configured for the eCall feature.
English/Metric Display Mode	IPC	ACM	Indicates whether English or metric units is currently selected.
FCIM Button State	FCIM	ACM APIM Audio DSP module IPC RETM	Indicates when a button is pressed on the FCIM so the audio system can make the desired setting change.
HVAC Module Display Data	HVAC module	ACM	Indicates certain climate control settings such as temperature, fan speed, air distribution, and outside air temperature.
HVAC System Button Status (From ACM)	ACM	HVAC module	Indicates when a climate control setting is changed using the FDIM touchscreen (which is hardwired to the ACM) so the HVAC module can make the desired setting change.
HVAC System Button Status (From FCIM)	FCIM	HVAC module	Indicates when a climate control button is pressed on the FCIM so the HVAC module can make the desired setting change.
HVAC System Indication Command (To ACM)	HVAC module	ACM	Indicates the mode of the HVAC module so the ACM can send the correct display information to the FDIM. This message only applies to vehicles with navigation.
HVAC System Indication Command (To FCIM)	HVAC module	FCIM	Indicates the mode of the HVAC module so the FCIM can illuminate the appropriate indicator on the bezel face.
HVAC System Voice Request Status	ACM	HVAC module	Provides climate control setting changes that are initiated through the voice recognition system. This message only applies to vehicles with navigation.
Ignition Switch Position	SJB	ACM APIM FCIM Audio DSP module RETM	Indicates the ignition position to the audio system modules in order to control power management.
Illumination Dimmer Level	SJB	ACM FCIM RETM	Controls the backlight intensity, based on the position of the dimmer switch.
MyKey™	IPC	ACM	Provides the current MyKey™ type to the ACM for use with the volume limiter and Belt-Minder® chime audio mute features.
Navigation Radio Rolling Wheel Count	IPC	ACM	Provides for more accurate tracking of the vehicle position when the GPS signal is temporarily unavailable. This message only applies to vehicles with navigation.
Odometer Rolling Count	PCM	APIM	Provides the odometer reading to the APIM in order to initiate maintenance interval notifications.
Transmission Selector (PRNDL) Range	IPC	ACM	For the navigation system, this signal is used for more accurate navigation tracking. For the parking assist system, this signal is used by the ACM to determine if it should enable the speaker mute feature if a parking aid tone sounds. For the rear view camera system, this signal is used by the ACM to determine if it should allow the video feed from the rear view camera to be shown on the FDIM.
Vehicle Speed	IPC	ACM Audio DSP module	Used by the ACM (or audio DSP module) for the speed-compensated volume function.
Vehicle Identification Number (VIN) Information	IPC	ACM	Provides the VIN to verify the correct modules are installed.
Volume Cutback	IPC	ACM Audio DSP module (THX® audio)	When this message is active, the speaker output is reduced to allow the parking aid tone to be more easily heard. The IPC does not generate this message; it gateways it from the Parking Aid Module (PAM).