GM Service Manual Online
For 1990-2009 cars only

Voltmeter Reading High or Low

Step

Action

Value(s)

Yes

No

1

Did you review the Starting and Charging operation and perform the necessary inspections?

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Go to Step  2

Go to Diagnostic Starting Point

2

  1. Turn ON the engine.
  2. Connect a volt meter across the battery terminals.

Is the voltage reading within specification?

13.0 - 16.0  V

Go to Step 4

Go to Step  3

3

Inspect the generator. Refer to Diagnostic System Check - Engine Electrical .

Does the generator operate properly?

--

Go to Diagnostic System Check - Engine Electrical

Go to Step 10

4

Compare the voltage reading at the battery to the voltage reading on the gauge in the instrument cluster.

Are the two readings within 1 volt?

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Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 5

5

  1. Disconnect the instrument cluster.
  2. Connect a volt meter from CKT 39 (PNK) to CKT 550 (BLK).

Is the reading within 1 volt of the reading at the battery?

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Go to Step 6

Go to Step 7

6

Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console.

Did you complete the replacement?

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Go to Step  11

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7

Measure for continuity from CKT 550 (BLK) cavity B4 to ground.

Is there continuity?

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Go to Step  9

Go to Step 8

8

Repair CKT 550 (BLK) wire.

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step  11

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9

Repair CKT 39 (PNK) wire.

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step  11

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10

Replace the Generator. Refer to Generator Replacement .

Did you complete the replacement?

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Go to Step  11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step  2