GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the IPC System Check?

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Go to Step 2

Go to IPC System Check

2

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Ensure that the wheels are off of the ground.

  3. Install a scan tool.
  4. Turn the ignition switch to the ON position.
  5. Ensure that the following conditions exist:

    • The engine is running.
    • The transmission is gear.
    • The wheels are spinning.
  6. Select the Vehicle Speed display on the scan tool.
  7. Compare the Vehicle Speed on the scan tool to the expected speed at which the vehicle is being driven.

Does the scan tool agree with the expected vehicle speed?

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Go to Step 3

Go to Step 5

3

Compare the Vehicle Speed displayed on the scan tool to the speed displayed on the speedometer.

Are the speeds within 4.8 km/h (3 MPH) (the symptom may be intermittent)?

--

Go to IPC 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 IPC System Check

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5

Inspect for a speed input to the IPC cluster at terminal A4.

Is there a speed signal input?

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. 1.1. CKT 389 (DK GRN) from the IP cluster to the vehicle control module for a short voltage.
    1.2. CKT 389 (DK GRN) from the IP cluster to the vehicle control module for an open.
    1.3. All of the electrical connectors for correct mating.
  3. Repair any conditions that you find.

Did you correct any of the above conditions?

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Go to IPC System Check

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