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 starter generator control module (SGCM) coolant pump does not operate.

1

Did you perform the Engine Cooling Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Engine Cooling

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the SGCM pump speed ON in Powertrain, Alternative fuels, special functions, SGCM output controls.

Does the SGCM coolant pump operate?

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

Go to Step 3

3

  1. Disconnect the SGCM cool pump relay.
  2. Connect a test lamp between the control circuit and the coil supply voltage circuit of the SGCM cool pump relay.
  3. With a scan tool command the SGCM pump speed ON and OFF.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4

Connect a 10-amp fused jumper wire between the battery positive voltage circuit and the coolant pump supply voltage circuit of the SGCM relay.

Does the coolant pump operate?

Go to Step 12

Go to Step 8

5

Test the control circuit of the SGCM cool pump relay for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 6

6

Test the battery positive voltage circuit of the SGCM cool pump relay for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 7

7

Test the voltage supply circuit of the SGCM coolant pump for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 10

8

Test the voltage supply circuit of the SGCM coolant pump for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 9

9

Test the ground circuit of the SGCM coolant pump for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 11

10

Replace the SGCM. Refer to Generator Control Module Replacement in Engine Electrical.

Did you complete the replacement?

Go to Step 13

--

11

Replace the SGCM coolant pump. Refer to Generator Control Module Coolant Pump Replacement .

Did you complete the replacement?

Go to Step 13

--

12

Replace the SGCM relay.

Did you complete the replacement?

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2