The instrument cluster uses information from other systems
in order to deliver information to the driver. Review the general information
on the following items before further diagnosis:
• | How the instrument cluster computer system operates. |
• | How each system interacts with the instrument cluster. |
This step may prevent the following conditions from occurring:
• | Unnecessary parts replacement |
Use a Scan Tool
in order to diagnose the instrument cluster when referred to the instrument
cluster in diagnostic procedures. In addition to displaying Diagnostic
Trouble Codes (DTCs), the Scan Tool
display may display the following information:
The Scan Tool
may
also cycle many of the following components both on and off.
Any of these features may be selected using the Scan Tool
.
Become very familiar with the following instrument cluster information:
• | The diagnostic features |
The self-diagnostic features are referenced in the DTC tables. These
features are very useful in diagnosing non-DTC setting malfunctions as well.
Not all circuits that feed information to the instrument cluster will
set a code if the fault exists within that circuit. The following circuits
will not set a trouble code:
• | The windshield washer solvent level switch input |
• | The engine coolant level indicator module switch inputs |
The diagnostic tables concerning these circuits are still included within
this cell in order to help locate the concerns. Perform the Instrument Cluster
Diagnostic System Check, these tables will assist in diagnosis.
Replace the instrument cluster only if the diagnostic procedures specifically
direct you in order to do so. The instrument cluster does not automatically
need to be replaced when a short is found in the wiring. Repair the
wiring first. Inspect the system for further concerns. Most system malfunctions
are traceable to one of the following conditions:
The instrument cluster is very reliable. The instrument cluster is usually
not the cause of a system malfunction. Replacing the instrument cluster before
a complete diagnosis will usually result in a recurrence of the original
complaint.
Display Input Status
The Scan Tool
also
displays the instrument cluster status. Select the instrument cluster status
display in order to display the data. Determine if the switched inputs
may be properly interpreted. The display also indicates if the input
has changed states. For example, when the engine coolant level is OK,
the Scan Tool
displays
the input status of the engine coolant level switch as INACTIVE. When
the engine coolant level is low, the scan tool reads ACTIVE. Use this
kind of information when diagnosing a malfunction associated with one
of the following conditions:
• | A particular instrument cluster input. |
• | An input that is shared using another system. |
Cycle Indicators and Gauges
Use a Scan Tool
in order to cycle the following instrument cluster components:
This feature may be used in order to determine if the instrument cluster
is able to cycle the indicator or gauge regardless of the condition following
components:
• | Any specific program instructions. |
Once a test is selected, the Scan Tool
will command the instrument cluster in order to energize
the selected indicator or gauge. The displayed information represents
only what the instrument cluster commands. The displayed information
does not display what action has actually taken place. Inspect the instrument
cluster for the ability in order to control each of the selected indicator
and gauge functions.
Intermittents and Poor Connections
Intermittent failures in electronic systems may be very difficult to
detect and accurately diagnose. The instrument panel cluster tests for
different malfunctions under different vehicle conditions. For this reason,
a thorough test drive is often needed in order to repeat a fault condition.
If the system malfunction is not repeated during the drive test, a good
description of the complaint may be useful in locating an intermittent
fault condition. The following faulty components cause most intermittent
problems:
When you suspect an intermittent condition, inspect the suspected circuits
for the following conditions:
• | Poor mating of the connector halves. |
• | Improperly formed or damaged terminals. |
• | Poor wire-to-terminal connections. |
• | Dirty or corroded terminals. |
• | Damage to the connector bodies. |
The history DTCs indicate that the instrument cluster has previously
detected a malfunction. The reason may be one of the following conditions:
• | The malfunction is intermittent. |
• | The system for which the DTC is set for is not currently being
operated. |
Use a Scan Tool
in order to try clearing the DTCs and manually operating the system that the
DTC applies to, if the following conditions occur:
• | The instrument cluster displays history DTCs. |
• | The malfunction cannot be found easily. |
Read the Diagnostic Aids and Conditions for Setting the DTC in each
DTC table for more specific information.
History DTCs help in diagnosing the intermittent fault conditions but
do not necessarily indicate a faulty instrument cluster. Most system complaints
are linked to the following conditions:
Perform a thorough inspection of all the related wiring and connectors
pertaining to the history DTC that is stored.
The following conditions my result in an intermittent instrument cluster
operation using no DTC stored:
• | Any condition which results in the interruption of power to the
instrument cluster. |
• | The battery or ignition voltage out of range (below 9.0 V
or above 16.0 V). |
• | A loose or damaged ground. |
• | An open or short on the serial data line. |
DTCs Current and History
The instrument cluster stores the DTCs as one of the following codes:
If the instrument cluster detects a system malfunction, the instrument
cluster will only store a DTC that corresponds to that particular malfunction.
Some DTCs may remain current until the first ignition cycle if the
following conditions occur:
• | A current DTC is stored. |
• | The fault is no longer present. |
Other DTCs will go history under the following conditions:
• | The fault is no longer present. |
• | The fault does not require an ignition cycle. |
The history DTCs are intermittent malfunctions. These must be diagnosed
differently than the current DTCs. Refer to
Intermittents and Poor Connections Diagnosis
in Wiring Systems.