Principles of Operation (How Does It Work?)

PRINCIPLES OF OPERATION

The message center is a vacuum fluorescent display, part of the instrument cluster. The message center electronic functions use both hardwired, standard corporate protocol (SCP), and UART based protocol (UBP) communication networks 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 SCP communication network 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 three buttons:
- INFO
- SETUP
- RESET

Information Displays
The information displays are non-timed modes. The selected mode remains on until the driver depresses a message center button to change the mode or it is overridden by another mode. The information display modes are:
- odometer
- trip odometer
- compass
- distance to empty
- average fuel economy

For additional information regarding the odometer and trip odometer, refer to Instrument Cluster.

Setup Displays
The setup displays are timed modes and terminate after a finite interval. The setup display modes are:
- language
- English/metric units
- system check
- charge system status
- oil pressure status
- engine temp status
- washer fluid status
- brake fluid status
- fuel level status
- distance to empty
- tire warning

Every 180 days or 8,000 km (5,000 miles) the OIL LIFE display in the message center SYSTEM CHECK will decrease gradually from 100% to 0%. At 5% oil life, the CHANGE OIL SOON warning indicator will illuminate. At 0% oil life, the OIL CHANGE REQUIRED warning indicator will illuminate. OIL LIFE status is continually displayed in the SYSTEM CHECK portion of the message center and OIL LIFE warnings appear if OIL LIFE is low. For additional information, refer to the owner literature.

Warning Messages
The warning messages are single cycle, non-resettable and repetitive warning messages. The single cycle warning messages are:
- CHANGE OIL SOON
- OIL CHANGE REQUIRED
- LOW WASHER FLUID LEVEL
- LOW BRAKE FLUID LEVEL
- POWER LIFTGATE
- POWER RUNNING BOARDS

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 repetitive warning messages are:
- CHECK CHARGING SYSTEM
- TRANSMISSION OVERHEATED
- CHECK TRANSMISSION
- LOW FUEL LEVEL
- LOW OIL PRESSURE
- CHECK ENGINE TEMPERATURE
- CHECK TIRES
- CHECK FUEL CAP

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 only reoccur after 10 minutes or until the warning condition is corrected.

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 are:
- DOOR AJAR
- BACKUP AID