GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Turn ON the ignition, with the engine OFF.

Does the boost gage perform a self test by the gage dial moving to 0 kPa (0psi) when the ignition is turned ON?

Go to Step 5

Go to Step 3

3

  1. Turn ON the ignition, with the engine OFF.
  2. Disconnect the boost gage.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the boost gage ignition 1 voltage circuit and a good ground.

Does the test light illuminate?

Go to Step 4

Go to Step 6

4

Connect a test lamp between the boost gage ignition 1 voltage circuit and the boost gage ground circuit.

Does the test light illuminate?

Go to Step 9

Go to Step 7

5

Test the boost gage signal circuit for the following:

    • An open
    • A high resistance
    • A short to ground

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 8

6

Test the ignition 1 voltage circuit to the boost gage for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 9

7

Test the ground circuit of the boost gage for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

Inspect for a poor connection at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Replace the boost gage. Refer to Supercharger Boost Air Pressure Indicator Replacement .

Did you complete the replacement?

Go to Step 11

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10

Replace the ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 4

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2