Principles of Operation

PRINCIPLES OF OPERATION

The message center is a vacuum fluorescent display, which is part of the instrument cluster. The message center electronic functions use both hardwired and controller area network (CAN) circuits to transmit and receive information. As a technician it is very important to understand:
- where the input (command) originates from.
- all the information (messages) necessary in order for a feature to operate.
- which module(s) receive(s) the input or command message.
- does the module which received the input (message) control the output of the feature, or does it output a message over the CAN circuits to another module.
- which module controls the output of the feature.

The message center provides the following features:
- information displays
- setup displays
- warning messages
- system check messages

The message center information can be selected through a set of 3 buttons:
- SET
- INFO
- RESET

The message center buttons are located on the steering wheel assembly, behind the steering wheel audio control buttons.

Information Displays
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 ododmeter
- distance to empty
- average fuel economy
- fuel used
- trip elapsed drive time
- compass

System Check
Selecting this function from the SETUP menu causes the message center to cycle through each of the systems being monitored. For each of the monitored systems, the message center indicates either an OK message or a warning message for 2 to 4 seconds. The system check report is as follows:
- OIL LIFE STATUS/RESET
- DOOR AJAR STATUS
- DRIVER DOOR AJAR STATUS
- PASSENGER DOOR AJAR STATUS
- LEFT REAR DOOR AJAR STATUS
- RIGHT REAR DOOR AJAR STATUS
- LIFTGATE AJAR STATUS
- TRUNK AJAR STATUS
- ENGINE TEMP
- CHARGING SYSTEM
- BRAKE SYSTEM
- PARK BRAKE STATUS
- OIL PRESSURE STATUS
- WASHER FLUID LEVEL STATUS
- BRAKE FLUID LEVEL
- COOLANT LEVEL STATUS
- TRANSMISSION STATUS
- TRACTION CONTROL
- ADV TRAC SYSTEM STATUS
- AWD SYSTEM STATUS
- FUEL LEVEL STATUS
- DTE STATUS

Warning Messages
The warning messages are single cycle, non-resettable and repetitive. The single cycle warning messages display once whenever the ignition switch is turned to the ON position or a fault occurs in a system, and can be cleared by pressing the RESET button.

The signal cycle warning messages are:
- LIFTGATE AJAR
- TRUNK AJAR
- CHECK ENGINE
- CHECK TRACTION CONTROL
- FUEL GAUGE Op 1/2 to E Only
- LOW COOLANT LEVEL
- OIL LIFE 0%, CHANGE OIL
- OIL LIFE XX%, CHANGE SOON
- LOW BRAKE FLUID LEVEL
- LOW WASHER FLUID
- TURN SIGNAL ON

The repetitive warning messages are displayed at a fixed interval whenever the ignition switch is turned to ON or is in the ACC position. To remove a repetitive warning message, press the RESET button. The message reoccurs after 10 minutes or until the warning condition is corrected.

The repetitive warning messages are:
- CHECK ENGINE TEMP
- CHECK CHARGING SYSTEM
- ENGINE FAILSAFE MODE
- TRANSMISSION OVERHEATED
- AWD MALFUNCTION
- CHECK BRAKE SYSTEM
- CHECK TRANSMISSION
- LOW FUEL LEVEL
- OIL PRESSURE LOW
- CHECK FUEL CAP

The non-resettable warning messages display whenever the ignition switch is turned to ON and a fault occurs in a system. The fault must be corrected to clear the non-resettable warning messages.

The non-resettable warning messages is:
- DRIVER'S DOOR AJAR
- PASSENGER'S DOOR AJAR
- LEFT REAR DOOR AJAR
- RIGHT REAR DOOR AJAR
- PARK BRAKE ENGAGED