Instrument Cluster
The instrument cluster is centered above the steering column in the instrument panel and is removable from the rear of the panel (toward the steering wheel). The cluster contains instruments that provide the driver with information on the vehicle performance. The instrument cluster consists of the following components:
| • | The speedometer (with integral odometer and trip odometer) |
| • | A tachometer |
| • | A fuel gauge |
| • | An engine coolant temperature gauge |
| • | An array of warning and indicator lamps |
The instrument cluster assembly consists of the lens and the speedometer/tachometer gauge module. The electrical power is directed to each gauge through a separate, dedicated wiring harness connector, and to the individual lamps and gauges within each module by flexible printed circuits. While the instrument cluster is serviceable as both a unit and as individual components, the individual gauge modules are not to be disassembled (each gauge module may be removed from the cluster lens for module or lens replacement).
Federal law requires that the reading of a replacement odometer be set to the original mileage or a label be installed on the driver door frame in order to indicate the previous odometer reading and the date of the replacement. Since the mileage cannot be set on the odometer in this vehicle, the odometer label must be used.
IPC Service Precautions
The instrument panel cluster (IPC) is designed to withstand normal current drains associated with vehicle operations. Care must be used in order to avoid overloading any of these 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 procedure. These circuits should only be tested using a J 39200 digital multimeter (DMM) while they remain connected to the IPC. Refer to
Notice: Electrostatic discharge (ESD) can damage many solid-state electrical components.
ESD susceptible components may or may not be labeled with the ESD symbol. Handle
all electrical components carefully. Use the following precautions in order to avoid
ESD damage:
• Touch a metal ground point in order to remove your body's static charge
before servicing any electronic component; especially after sliding across the vehicle
seat. • Do not touch exposed terminals. Terminals may connect to circuits susceptible
the ESD damage. • Do not allow tools to contact exposed terminals when servicing connectors. • Do not remove components from their protective packaging until required
to do so. • Avoid the following actions unless required by the diagnostic procedure: - Jumpering or grounding of the components or connectors. - Connecting test equipment probes to components or connectors. Connect
the ground lead first when using test probes. • Ground the protective packaging of any component before opening. Do not
rest solid-state components on metal workbenches, or on top of TVs, radios, or other
electrical devices.
Diagnostic System
The instrument panel cluster (IPC) is equipped with an extensive diagnostic system. This system is capable of detecting, compensating for, and alerting the driver of a malfunction. The IPC displays a warning message and/or sets a diagnostic trouble code (DTC) when a malfunction is detected.
Diagnostic Trouble Codes (DTCs)
Diagnostic trouble codes (DTCs) indicate that the instrument panel cluster (IPC) has detected a malfunction in a particular circuit or system. The IPC is programmed with routines for internal tests that are followed only under prescribed test conditions. When these conditions exist, the IPC tests certain circuits or systems for malfunctioning. When a fault condition is true, a DTC is set current. Some DTCs command the IPC to illuminate the SERVICE VEHICLE SOON indicator.
DTCs are not stored in the IPC's EEPROM and so are not retained after a battery disconnection.
Current DTCs
When the instrument panel cluster (IPC) determines that the test conditions and fault conditions for a particular diagnostic trouble code (DTC) are true, the DTC is set current. All DTCs remain set current at least until the next time the IPC finds the test conditions are true and the fault conditions are false. A few DTCs remain current until the next time the ignition is cycled or until the fault conditions are false several times.
History DTCs
When a diagnostic trouble code (DTC) has been set, the instrument panel cluster (IPC) continues to monitor for test conditions and for failure conditions. For most DTCs, if the test conditions are true while the fault conditions are false, the DTC is changed to history. Some DTCs require the test conditions to be true and the fault conditions to be false several times or require an ignition cycle to change from current to history. If there are no current DTCs for a period of 50 ignition cycles, all history DTCs will be cleared.
IPC EEPROM
Important: The electrically erasable programmable read only memory (EEPROM) is soldered into the instrument panel cluster (IPC) and cannot be serviced separately.
The IPC contains a data storage device which can save critical data even when battery power is removed. The EEPROM is used by the IPC in order to store the following information:
| • | The odometer readings |
| • | The options settings |
| • | The manufacturing information |
IPC Keep Alive Memory
Important: The keep alive memory (KAM) area is an integral part of the instrument panel cluster (IPC) microprocessor and cannot be serviced separately.
The IPC contains a data storage area which saves pertinent data when the ignition is turned off. This data is lost when battery power is interrupted. The KAM is used by the IPC in order to store the following information:
| • | The trip odometer readings |
| • | The fuel data information |
| • | The DTCs |
Dimming
The instrument panel cluster (IPC) displays, other than the indicators, are dimmable. The IPC backlighting (graphics and pointers) is controlled directly by the dash integration module (DIM) through the instrument panel (IP) dimmer switch. The IPC receives the dimming status through a class 2 message from the DIM.
