Principles of Operation: Notes

The instrument cluster is a configurable, hybrid electronic cluster (HEC) that contains a microprocessor, gauges, indicator lamps and internal circuitry. Prior to removal of the instrument cluster, it is necessary to upload module configuration information to the diagnostic tool. This information needs to be downloaded into the new instrument cluster. For additional information, refer to MODULE COMMUNICATIONS NETWORK . The following configurable items for the instrument cluster are:

• Fuel gallon display
• Language type
• Oil life warning threshold
• Tire pressure monitoring
• Belt minder
• Oil life status
• Fuel computer
• Back-up aid warning

The instrument cluster is non-repairable, with the exception of the instrument cluster lens. The instrument cluster utilizes hardwired circuitry, the standard corporate protocol (SCP), and the universal asynchronous receiver-transmitter (LJART) based protocol (UBP) communication networks to send and receive data. Communication using the SCP network transmits and receives data interactively between the instrument cluster, the power train control module (PCM) and the anti-lock brake system (ABS) module. Communication using the UBP network transmits and receives data interactively between the instrument cluster, all-wheel drive (AWD) control module, vehicle security module and the driver seat module. In addition, the instrument cluster is used as a gateway, or distribution module, for data messages used by other modules over the UBP communication network. For additional information regarding the SCP and UBP communication networks, refer to MODULE COMMUNICATIONS NETWORK .

The instrument cluster carries out a 6 second prove-out when the key is transitioned from the OFF to the RUN position to verify the integrity of the air bag warning indicator. The charging system warning indicator, the low oil pressure warning indicator and the malfunction indicator lamp (MIL) illuminates when the key is turned to the ON position, and then will turn off when the engine is started. The following indicators will prove-out when the key is turned to the ON position:

• Anti-lock brake system (ABS) warning indicator (3 seconds)
• Brake warning indicator (3 seconds)
• AWD indicator (3 seconds)
• Safety belt warning indicator (60 seconds)
• Traction control indicator (3 seconds)
• Low oil pressure warning indicator
• Engine coolant temperature warning indicator (3 seconds)
• Low tire warning indicator (3 seconds)