GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Is the low coolant warning indicator on with the coolant level OK?

--

Go to Step 3

Go to Step 2

2

Does the low coolant warning indicator remain off when the coolant level is low?

--

Go to Step 8

System OK

3

  1. Disconnect the engine coolant level indicator module.
  2. Turn the ignition switch on.

Is the low coolant warning indicator on?

--

Go to Step 5

Go to Step 4

4

Replace the engine coolant level indicator module. Refer to Coolant Level Module Replacement in Engine Cooling.

Is the repair complete?

--

Go to Step 18

--

5

  1. Turn the ignition switch off.
  2. Leave the engine coolant level indicator module disconnected.
  3. Disconnect the instrument cluster.
  4. Using a DMM, measure the resistance between the instrument cluster harness connector terminal B and ground.

Is the measured resistance same as the specified value?

Go to Step 7

Go to Step 6

6

Repair short to ground in circuit 68.

Is the repair complete?

--

Go to Step 18

--

7

Replace the instrument cluster. Refer to Instrument Cluster Replacement for service procedure.

Is the repair complete?

--

Go to Step 18

--

8

  1. Disconnect the engine coolant level indicator module.
  2. Turn the ignition switch on.
  3. Connect a 3A fused jumper between the engine coolant level indicator module harness connector terminal B and ground.

Is the low coolant warning indicator on?

--

Go to Step 9

Go to Step 16

9

  1. Remove fused jumper from previous step.
  2. Connect a 3A fused jumper between the engine coolant level indicator module harness connector terminal B and terminal C.

Is the low coolant warning indicator on?

--

Go to Step 10

Go to Step 11

10

Replace the engine coolant level indicator module. Refer to Coolant Level Module Replacement in Engine Cooling.

Is the repair complete?

--

Go to Step 18

--

11

  1. Disconnect the underhood accessory wiring junction block connector C1.
  2. Check for a poor connection or an open in circuit 451 between the underhood accessory wiring junction block harness connector C1 terminal A7 and ground.

Is there a poor connection or open in circuit 451?

--

Go to Step 12

Go to Step 13

12

Repair poor connection or open in circuit 451.

Is the repair complete?

--

Go to Step 18

--

13

Check for a poor connection or open in circuit 451 between the engine coolant level indicator module harness connector terminal C and the underhood accessory wiring junction block harness connector C1 terminal  B3.

Is there a poor connection or open in circuit 451?

--

Go to Step 14

Go to Step 15

14

Repair the poor connection or the open in circuit 451 between the engine coolant level indicator module harness connector terminal C and the underhood accessory wiring junction block harness connector C1 terminal B3.

Is the repair complete?

--

Go to Step 18

--

15

Replace the underhood accessory wiring junction block. Refer to Underhood Fuse Block Replacement in Engine Electrical.

Is the repair complete?

--

Go to Step 18

--

16

  1. Turn the ignition switch off.
  2. Leave the fused jumper connected between the engine coolant level indicator module harness connector terminal B and ground.
  3. Remove the instrument cluster.
  4. Using a DMM, measure the resistance between the instrument cluster harness connector terminal B4 and ground.

Is the measured resistance within the specified value?

Less than 3ohms

Go to Step 7

Go to Step 17

17

Repair poor connection or open in circuit 68.

Is the repair complete?

--

Go to Step 18

--

18

  1. Turn the ignition switch off.
  2. Reconnect connectors/components removed.
  3. Clear instrument panel Diagnostic Trouble Codes (DTCs). Refer to Clearing DTCs for more information.
  4. Check for instrument cluster DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying for more information.

Are there any instrument cluster DTCs present?

--

Go to Diagnostic Trouble Code (DTC) List/Type

System OK