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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 691 (ENGINE COOLING SYSTEM (1 OF 2))DIAGNOSTIC INFORMATION AND PROCEDURESSTARTER GENERATOR CONTROL MODULE COOLANT PUMP INOPERATIVE
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6

Starter Generator Control Module Coolant Pump Inoperative

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Starter Generator Control Module Coolant Pump Inoperative
WARNING: This page is about a different car, the 2006 GMC Sierra, 2006 GMC Cab & Chassis Sierra, 2006 Chevrolet Silverado, and 2006 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Starter Generator Control Module Coolant Pump Inoperative

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 under certain conditions.
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2 SGCM and red box are the same part.
  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 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 red box cool pump relay.
  2. Connect a test lamp between the control circuit and the coil supply voltage circuit of the red box 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 after-boil relay.
Does the after-boil coolant pump operate?		 Go to Step 12  Go to Step 8 
5 Test the control circuit of the red box 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 red box 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 red box 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 red box 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 red box 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 (red box). Refer to Starter/Generator Control Module (SGCM) Replacement (5.3L Engine w/RPO HP2) in Engine Electrical.
Did you complete the replacement?		 Go to Step 13  -
11 Replace the red box coolant pump. Refer to Coolant Pump - Starter/Generator Control Module Replacement .
Did you complete the replacement?		 Go to Step 13  -
12 Replace the red box 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 
RENDER: 1.0x

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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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