Test Description

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Test Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number on the diagnostic table.

  1. 2:  This step checks that the VCIM is sending out the proper supply voltage.
DTC B2476

Step Action Values Yes No
Schematic Reference: OnStar Schematics 
Connector End View Reference: Entertainment/Communication Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
  1. Turn the ignition OFF.
  2. Disconnect the rearview mirror assembly connector.
  3. Turn the ignition ON, with the engine OFF.
  4. Measure the voltage from the keypad supply voltage circuit to a good ground.
Does the voltage measure greater than the specified value?
9 V Go to Step 4  Go to Step 3 
3 Test the keypad supply voltage circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
- Go to Step 11  Go to Step 8 
4 Test the keypad supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
- Go to Step 11  Go to Step 5 
5 Test the keypad ground circuit for an open. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
- Go to Step 11  Go to Step 6 
6 Test the keypad signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
- Go to Step 11  Go to Step 7 
7 Inspect for poor connections at the harness connector of the rearview mirror. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
- Go to Step 11  Go to Step 9 
8 Inspect for poor connections at the harness connector of the vehicle communication interface module (VCIM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
- Go to Step 11  Go to Step 10 
9 Replace the rearview mirror. Refer to Rearview Mirror Replacement .
Did you complete the replacement?
- Go to Step 11  -
10 Replace the VCIM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?
- Go to Step 11  -
11
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?
- Go to Step 2  System OK
RENDER: 1.0x

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When to See a Mechanic

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

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.