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

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
- distance to empty
- average fuel economy
- trip odometer
- trip elapsed drive time
- compass (if equipped)

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 will indicate either an OK message or a warning message for two to four seconds. The sequence of the system check report is as follows:
- OIL PRESSURE
- CHARGING SYSTEM
- BRAKE FLUID LEVEL
- FUEL LEVEL
- DOOR AJAR
- PARK BRAKE STATUS
- ENGINE TEMP
- BRAKE SYSTEM
- TRACTION CONTROL (if equipped)

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

The signal cycle warning messages are:
- LOW COOLANT LEVEL
- LOW BRAKE FLUID
- LIFTGATE AJAR (if equipped)
- CHECK TRACTION CONTROL (if equipped)

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

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

The non-resettable warning messages will 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:
- DOOR AJAR
- PARK BRAKE ENGAGED