GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Engine Cooling Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Low Coolant Level parameter in the instrument cluster (IPC) data list.

Does the scan tool display OK?

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

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the engine coolant level switch.
  3. Connect a 3 amp fused jumper between the signal circuit of the engine coolant level switch and the ground circuit of the engine coolant level switch.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the Low Coolant Level parameter.

Does the scan tool display OK?

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Go to Step 7

Go to Step 4

4

Test the ground circuit of the engine coolant level switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 10

Go to Step 5

5

Test the signal circuit of the engine coolant level switch for the following conditions:

    • An open
    • A short to voltage
    • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the instrument cluster (IPC). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the engine coolant level switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

8

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

Did you complete the replacement?

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Go to Step 10

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9

Replace the engine coolant level switch. Refer to Radiator Surge Tank Replacement .

Did you complete the replacement?

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Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2