Principles Of Operation

NOTE: The instrument cluster, front electronic module (FEM), and the rear electronic module (REM) must be reconfigured upon installation. Refer to MODULE COMMUNICATIONS NETWORK .

NOTE: The diagnostic tool may display ICM for the instrument cluster.

NOTE: For any concerns with the restraint control module (RCM), refer to AIR BAG RESTRAINT SYSTEMS .

NOTE: The instrument cluster is not repairable at the dealership with the exception of the instrument cluster lens. Do not disassemble the instrument cluster.

The instrument cluster is a hybrid electronic instrument cluster (HEC). The vehicle electronic functions are divided into zones. The instrument cluster, FEM, and REM use the standard corporate protocol (SCP) communication network to transmit and receive information. It is very important to understand:

where the input (command) originates from.
all information (messages) necessary in order for a feature to operate.
which module(s) receive(s) the input or command message.
whether the module which received the input (message) controls the output of the feature, or whether it outputs a message over the SCP communication network to another module.
which module controls the output of the feature.

The instrument cluster communicates with the FEM, REM, anti-lock brake system/traction control (ABS/TC), powertrain control module (PCM), and the RCM over the SCP communication network to control the gauges, indicators, and chimes.

The instrument cluster carries out a display prove-out to verify the integrity of the cluster controlled indicators. When the key is in the ON position with the engine off, the following warning indicators will prove out:

BRAKE warning indicator
anti-lock brake system (ABS) warning indicator
engine over-temperature warning indicator
traction control
low fuel indicator
low washer fluid warning indicator
CHECK FUEL CAP indicator

There are three indicators that also maintain a prove-out but are controlled by other modules. The air bag warning indicator prove-out is controlled by the RCM, the check engine indicator is controlled by the PCM and the charging system warning indicator is controlled by the PCM.