Principles of Operation

PRINCIPLES OF OPERATION

The message center electronic functions use both hardwired, and controller area network (CAN) circuitry to transmit and receive information. As a technician, it is very important to understand:
- where the input (command) originates.
- all the information (messages) necessary in order for a feature to operate.
- which module(s) receive(s) the input or command message.
- if the module that received the input (message) controls the output of the feature, or if it outputs a message over the CAN to another module.
- which module controls the output of the feature.

The message center provides the following features:
- Information displays
- Setup displays
- System check messages
- System warning messages

The message center information is selected through a set of 3 buttons:
- INFO
- SETUP
- RESET

Information Displays (INFO button)
The information displays are non-timed modes. The selected mode remains on until the driver presses a message center button to change the mode or it is overridden by another mode. The information display modes are:
- Odometer
- Trip odometer A or B
- Distance to empty (DTE)
- Average fuel economy
- Average speed
- Compass (if equipped)
- Trip elapsed drive time

Setup Displays (SETUP button)
The setup displays are timed modes and terminate after a finite interval. The setup display modes are:
- System check

- NOTE: Pressing the message center switch SETUP button, the message center displays the current units to be displayed. Refer to the Owner's Literature for more information.

Units (English/metric)

- Language

System Check Messages (RESET button)
By pressing the RESET button on the message center switch, the message center cycles through each of the system check messages being monitored. For each of the monitored systems, the message center indicates either an OK message or a warning message for 2-4 seconds.

The system check messages are:
- DOORS CLOSED
- ENGINE TEMPERATURE
- CHARGING SYSTEM
- OIL PRESSURE
- BRAKE FLUID LEVEL
- EXTERIOR LAMPS
- FUEL LEVEL
- DISTANCE TO EMPTY (DTE)

System Warning Messages
System warnings alert the operator to possible problems or malfunctions in the vehicle operating system. When multiple warnings are displayed, the message center cycles all the warnings by displaying each one for several seconds.

The message center displays the last selected feature if there are no more warning messages. This allows full functionality of the message center by pressing the message center switch RESET button to clear the warning message. Warning messages that have been reset are divided into 3 categories where the message:
- does not disappear until a condition has changed.
- will reappear 10 minutes after pressing the RESET button.
- does not reappear until the ignition switch LOCK/OFF to RUN cycle has been completed. This acts as a reminder that the warning conditions still exist on the vehicle.

The system warning messages that cannot be reset are:
- DRIVER DOOR AJAR
- PASSENGER DOOR AJAR
- REAR LEFT DOOR AJAR
- REAR RIGHT DOOR AJAR
- PARK BRAKE ENGAGED

The system warning messages that return after 10 minutes are:
- LOW FUEL LEVEL
- CHECK CHARGING SYSTEM
- CHECK BRAKE SYSTEM

The system warning messages that return after the ignition switch is turned from the LOCK/OFF to RUN position are:
- LOW BRAKE FLUID LEVEL
- TRUNK AJAR
- COMPASS ERROR (if equipped)
- CHECK LEFT HEADLAMP
- CHECK RIGHT HEADLAMP
- CHECK LF TURN LAMP
- CHECK RF TURN LAMP
- CHECK LR TURN LAMP
- CHECK RR TURN LAMP
- INTEGRATED KEY PROGRAMMING STATUS (displayed when an attempt is made to program a fifth integrated key to the remote keyless entry (RKE) system) - only allows 4 integrated keys.