GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Instrument Cluster System Check?

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Go to Step 2

Go to Instrument Cluster System Check

2

  1. Turn the ignition switch to the ON position with the engine running.
  2. Install the scan tool.
  3. Select the Engine Speed display on the scan tool.
  4. Compare the engine speed displayed on the scan tool to the expected engine speed for the vehicle conditions.

Is the engine speed within the specified range?

500-700 RPM at idle

Go to Step 3

Go to Step 5

3

Compare the engine speed display on the scan tool to the speed displayed on the tachometer.

Are the RPMs within 300 RPM of each other (the symptom may be intermittent)?

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Go to Instrument Cluster System Check

Go to Step 4

4

Replace the IP cluster. Refer to Instrument Cluster Replacement .

Is the repair complete?

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Go to Instrument Cluster System Check

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5

Using a DMM, inspect for RPM input to the IPC cluster at terminal A3.

Is the RPM signal input within the specified range?

3-5 VAC (on RMS scale)

Go to Symptoms in Engine Controls - 2.2L or Symptoms in Engine Controls - 4.3L

Go to Step 6

6

  1. Inspect the following items:
  2. • The circuit from the IP cluster to the VCM/PCM for a short to voltage or ground.
    • The circuit from the IP cluster to the VCM/PCM for an open.
    • All of the electrical connectors for correct mating.
  3. Repair any conditions that you find. Refer to Wiring Repairs

Is the repair complete?

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Go to Instrument Cluster System Check

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