GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Component Connector End Views

1

Did you review the Instrument Panel, Gages and Console Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Instrument Cluster Description and Operation

2

Verify that the engine coolant temperature (ECT) gage is inaccurate or inoperative.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Test cavity 1 of the ECT sensor for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 4

Go to Step 5

4

Disconnect the ECT sensor.

Does the ECT gage move to the cool position?

Go to Step 6

Go to Step 7

5

Repair open in the ECT ground signal circuit between cavity 1 of the ECT and C1 cavity 21 of SP108. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 10

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6

Replace the ECT sensor.

Did you complete repair complete?

Go to Step 10

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7

Test the ECT sensor signal circuit for an open or short to ground between cavity 2 of the ECT sensor and C1 cavity 9 of the powertrain control module (PCM). Refer to Circuit Testing and Wiring Repairs .

Did you find and complete the repair?

Go to Step 10

Go to Step 8

8

Test the ECT sensor signal circuit for an open or short to ground between cavity 36 of the instrument cluster and C3 cavity 14 of the PCM. Refer to Circuit Testing and Wiring Repairs .

Did you find and complete the repair?

Go to Step 10

Go to Step 9

9

Replace the instrument cluster. Refer to Instrument Cluster Replacement .

Did you complete the repair?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3