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Home >> GMC >> 2004 >> Envoy RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 19 (Cellular Communication System) >> Diagnostic Information and Procedures >> DTC B2476: Cellular Phone Select Service Switch Malfunction (3 Button Assembly) >> Test Description
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Test Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2005 Isuzu Ascender, 2005 GMC Envoy XUV, 2005 GMC Envoy XL, 2005 GMC Envoy, and 2005 Chevrolet TrailBlazer. 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: Cellular Communication Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2 
  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 in Wiring Systems.
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 in Wiring Systems.
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 in Wiring Systems.
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 in Wiring Systems.
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 in Wiring Systems.
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 in Wiring Systems.
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 in Stationary Windows.
Did you complete the replacement?		 - Go to Step 11  -
10 Replace the VCIM. Refer to Control Module References in Computer/Integrating Systems 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
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