GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Connector End View Reference:

1

Did you perform the Engine Cooling Diagnostic System Check?

Go to Step 2

Go to

2

  1. Verify that the engine coolant is at the proper level.
  2. Turn ON the ignition, with the engine OFF.

Does the IPC display Low Engine Coolant?

Go to Step 3

Go to in Wiring Systems

3

  1. Install a scan tool.
  2. With a scan tool, view the Coolant Level Switch data in the Engine Data 2 data list.

Does the scan tool display Low?

Go to Step 4

Go to Step 7

4

  1. Disconnect the coolant level sensor electrical connector.
  2. Connect a 3-amp fused jumper between the coolant level switch signal circuit of the coolant level sensor electrical connector and the ground circuit of the coolant level sensor electrical connector.
  3. With a scan tool, view the Coolant Level Switch data in the Engine Data 2 data list.

Does the scan tool display OK?

Go to Step 8

Go to Step 5

5

  1. Connect a 3-amp fused jumper between the coolant level switch signal circuit of the coolant level sensor electrical connector and a good ground.
  2. With a scan tool, view the Coolant Level Switch data in the Engine Data 2 data list.

Does the scan tool display OK?

Go to Step 10

Go to Step 6

6

Inspect the coolant level signal circuit for an open or short. Refer to and in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 9

7

Inspect for poor connections at the harness connector of the IPC. Refer to and in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 11

8

Inspect for poor connections at the harness connector of the coolant level sensor. Refer to and in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

9

Inspect for poor connections at the harness connector of the PCM. Refer to and in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

10

Repair the open in the ground circuit of the coolant level sensor. Refer to in Wiring Systems.

Did you Complete the repair?

Go to Step 14

--

11

Replace the IPC. Refer to in Instrument Panel, Gages and Console.

Did you Complete the repair?

Go to Step 14

--

12

Replace the coolant level sensor. Refer to in Engine Controls.

Did you Complete the repair?

Go to Step 14

--

13

Replace the PCM. Refer to in Engine Controls.

Did you Complete the repair?

Go to Step 14

--

14

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3