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 communication network 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 Mode
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:
- trip/total odometer
- trip odometer
- distance to empty
- average fuel economy
- fuel used
- instantaneous fuel economy
- trip elapsed drive time
- average speed
- blank display

Setup Mode
The setup mode provides a list of items that can be configured by the driver. The setup modes are:
- SYSTEM CHECK
- COLOR SELECTION
- UNITS (English/Metric)
- DISPLAY MODE (Single/Dual)
- LANGUAGES

Warnings Mode
A single chime sounds when a warning message is displayed. The warning messages display once whenever the ignition switch is turned to the ON position or a fault occurs in a system.

The warning messages are:
- DRIVER DOOR AJAR
- PASSENGER DOOR AJAR
- TRUNK AJAR
- CHECK CHARGING SYSTEM
- CHECK FUEL CAP
- CHECK TRAC CONTROL
- LOW BRAKE FLUID LEVEL
- BRAKE SYSTEM FAILURE
- PARK BRAKE ON
- LOW FUEL LEVEL
- LOW OIL PRESSURE
- TURN SIGNAL ON

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 sequence of the system check report is as follows:
- OIL PRESSURE OK
- CHARGING SYSTEM OK
- DRIVERS DOOR CLOSED
- PASSENGER DOOR CLOSED
- TRUNK CLOSED
- BRAKE SYSTEM OK
- TRAC CONTROL OK
- FUEL CAP OK
- FUEL LEVEL OK
- XXX MILES TO EMPTY