GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.

1

Was the Instrument Cluster Diagnostic System Check performed?

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Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

  1. Start the engine.
  2. Use the Scan Tool in order to read the BFC to cluster data.

Is the Tach Signal reading active?

--

Go to Step 5

Go to Step 3

3

  1. Disconnect the instrument cluster.
  2. Use the J 39200 DMM in order to measure the AC voltage in CKT 121 at connector terminal A7 of the instrument cluster.

Does an AC voltage exist?

--

Go to Step 4

Go to Step 5

4

Replace the instrument cluster. Refer to Instrument Cluster Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - Instrument Cluster

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5

Test for a short to ground in CKT 121.

Was a short to ground found?

--

Go to Step 6

Go to Step 7

6

Repair the short to ground in CKT 121. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - Instrument Cluster

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7

Use the J 39200 DMM in order to measure the resistance in CKT 121.

Does the resistance measure within the specified range?

0-2 ohms

Go to Step 9

Go to Step 8

8

Repair the open in CKT 121. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - Instrument Cluster

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9

Replace the powertrain control module (PCM). Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Is the repair complete?

--

Go to Diagnostic System Check - Instrument Cluster

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