GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

DEFINITION: The low engine coolant indicator is always ON and no powertrain DTCs have been set.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Turn ON the ignition, with the engine OFF.

Does the Low Coolant Level indicator illuminate?

Go to Step 3

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

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. Install a scan tool.
  5. Turn ON the ignition, with the engine OFF.
  6. Observe the Low Coolant Level parameter in the instrument cluster (IPC) data list.

Does the scan tool display OK?

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?

Go to Step 10

Go to Step 5

5

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

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the IPC. 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 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 IPC. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

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?

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 2