The instrument cluster serves as the primary interface for the vehicle's driver.

The instrument cluster communicates with other major electronic components over a class 2 serial data line.

The instrument cluster used in this vehicle is either a base or an uplevel (UB7). The following is a list of instrument cluster functions:

The instrument cluster has the capability to diagnose malfunctions in the following the cluster controls or to which the cluster communicates:

When the instrument cluster or other microprocessor-controlled module, detects a malfunction, the cluster may turn on an instrument cluster indicator or request/display a message to the driver information center (DIC). This alerts the driver that a malfunction has occurred. Some indicator lamps and instrument cluster messages have dual controls.

The IPC withstands normal current drains associated with vehicle operations. However, use care in order to avoid overloading any of the circuits. In testing for opens or shorts, do not ground or apply voltage to any of the IPC circuits unless instructed to do so by the diagnostic procedures.

The IPC has an extensive diagnostic system. The diagnostic system detects and compensates for malfunctions. The system alerts the operator of a malfunction. The IPC displays warning messages and/or sets a diagnostic trouble codes (DTCs) when the diagnostic system detects a malfunction.

The diagnostic trouble codes (DTCs) set in order to indicate that the IPC has detected a malfunction in a particular circuit or other system. The IPC's program follows routines for internal checks, but only under prescribed conditions (Test Conditions). When these conditions exist, the IPC evaluates certain circuits or systems for a malfunction (Failure Conditions). When the failure conditions are true, a DTC is set as a current DTC. Some DTCs command that the IPC illuminate the Service Vehicle Soon indicator.

The IPC's EEPROM does not store the DTCs. Therefore, the DTCs do not remain after a battery disconnect.

Current DTCs

When the IPC determines that the test conditions and failure conditions for a particular DTC are true, the IPC sets that DTC as current. All of the DTCs remain current at least until the next time the IPC finds the test conditions are true and the failure conditions are false. A few DTCs remain current until the next ignition cycle or until the failure conditions are false several times.

History DTCs

After a DTC has been set, the IPC continues to monitor for the test and failure conditions. For most DTCs, if the test conditions are true and the failure conditions are false, the DTC becomes a history DTC. Some of the DTCs require the test conditions to be true and failure conditions to be false several times. Some of the DTCs require an ignition cycle in order to change from current to history. If no current DTCs are present for a period of 50 ignition cycles, all of the history DTCs clear.

Important: The EEPROM is a soldered part of the IPC. Do NOT service the EEPROM separately.

The IPC contains a data storage device. the data storage device saves critical data even after the removal of battery power. The IPC uses the electrically erasable programmable read only memory (EEPROM) in order to store odometer readings, options settings and manufacturing information.

Important: The KAM area is an integral part of the IPC microprocessor. Do NOT service the KAM area separately.

The IPC contains a data storage area. The data storage area saves pertinent data when the ignition is in OFF. However, the IPC loses the data after removal of battery power. The IPC uses this area, the KAM, in order to store trip odometer readings, fuel data information and DTCs.

The uplevel instrument cluster contains a 32 character (2 lines x 16 characters) dot matrix configured message center called a driver information center (DIC). The DIC displays various messages to the driver. The DIC switches control the DIC.

The instrument cluster displays are dimmable. The indicators are non-dimmable. The instrument cluster incandescent backlighting (graphics and pointers) is directly controlled by the lighting control module (LCM) through a dimmer signal input. The instrument cluster monitors this input, and the dim enable signal input, in order to determine when to activate and the intensity of VF dimming.