GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Instrument Cluster Diagnostic System Check is an organized approach to identify problems associated with the module. This check must be the starting point for any module complaint, and will direct you to the next logical step in diagnosing the complaint. The module is a very reliable component and is not likely the cause of the malfunction. Most system complaints are linked to faulty wiring and connectors, and occasionally to components. Understanding the computer system and using the tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.

Diagnostic Aids

    • The following conditions may result in an intermittent operation of the module with no DTC stored:
       - Any condition which results in the interruption of power to the module
       - Out of range battery or ignition voltage

Specification
Normal module operating voltage: 9.0-16.0 V

       - A loose or damaged ground(s)
       - An open or shorted serial data line
    • An intermittent failure in the electronic system may be very difficult to detect and to accurately diagnose. The module tests for different malfunctions under different vehicle conditions. For this reason, a thorough test drive is often needed in order to repeat a malfunction. If the system malfunction is not repeated during the test drive, a good description of the complaint may be very useful in locating an intermittent malfunction. Faulty electrical connections or wiring causes most intermitting problems. When an intermitting condition is suspected, check the suspected circuits for the following conditions:
       - Poor mating of connector halves or backed out terminals
       - Improperly formed or damaged terminals
       - Wire chafing
       - Poor wire-to-terminal connections
       - Dirty or corroded terminals
       - Damage to connector bodies
    • Use the J 35616 whenever a diagnostic procedure requests probing or checking a terminal. Using this adapter will ensure that no damage to the terminal will occur, and will give an idea of whether contact tension is sufficient.
    • If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Perform a thorough inspection of all related wiring and connectors pertaining to the history DTC stored. Refer to Intermittents and Poor Connections Diagnosis .
    • Exit all scan tool tests before cycling the ignition OFF to ON unless the scan tool instructions direct otherwise. Follow the operating instructions in the scan tool operator's manual. Failure to follow these instruction may set DTCs, cause vehicle system malfunctions, set false DTCs, or cause scan tool malfunctions.

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. This test determines if communication can be established with the instrument cluster.

  2. This test checks for stored instrument cluster DTCs.

  3. This test determines whether communication can be established with other modules connected to the Class 2 serial data line.

  4. This test checks for any open instrument cluster power fuses.

  5. This test checks the instrument cluster power circuits. If the test light does not turn on, there is an open in the instrument cluster power circuit.

  6. This test checks the instrument cluster ground circuits. If the test light does not turn on, there is an open in the instrument cluster power circuit.

IPC Diagnostic System Check

Step

Action

Value(s)

Yes

No

1

  1. Turn the ignition switch to the OFF position.
  2. Connect a scan tool.
  3. Turn the ignition switch to the ON position.
  4. Attempt to establish communication with the instrument cluster.

Does the scan tool communicate with the instrument cluster?

--

Go to Step 2

Go to Step 3

2

Using the scan tool select display Instrument Cluster (IPC) DTC function.

Are any DTCs stored?

--

Go to Diagnostic Trouble Code (DTC) List/Type

Go to Instrument Cluster System Check

3

Attempt to establish communications with the other modules connected to the same serial data line (EBCM, PCM, SDM).

Does the scan tool communicate with the other modules?

--

Go to Step 4

Go to Data Link Communications Diagnostic System Ckeck

4

  1. Turn the ignition switch to the ON position.
  2. With a DMM connected to ground, probe each instrument cluster fuse.

Is the displayed voltage within the specified value?

10.5-12.5 V

Go to Step 5

Go to Step 7

5

  1. Turn the ignition switch to the OFF position.
  2. Remove the instrument cluster.
  3. Turn the ignition switch to the ON position.
  4. With a DMM connected to ground, probe all of the instrument cluster power circuits.

Is the displayed voltage within the specified value?

10.5-12.5 V

Go to Step 6

Go to Step 8

6

With a DMM connected to ground, probe all of the instrument cluster ground circuits at the instrument cluster connector (harness side).

Is the displayed resistance within the specified value?

0.0-0.5 ohms

Go to Data Link Communications Diagnostic System Ckeck

Go to Step 9

7

  1. Repair the open in the ignition or battery feed to instrument cluster fuse.
  2. If the fuse is open, check for a short to ground in the circuit connected to the open fuse.

Is the repair complete?

--

Go to Step 1

--

8

Locate and repair the open in the instrument cluster power circuit.

Is the repair complete?

--

Go to Step 1

--

9

Locate and repair the open in the instrument cluster ground circuit.

Is the repair complete?

--

Go to Step 1

--