LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2008 >> Escalade EXT >> Repair and Diagnosis (Single Page) >> External Pages >> Different car >> Section 8 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> DTC B2455 >> Test Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

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 B2455

Step Action Value(s) Yes No
Schematic Reference: OnStar Schematics 
Connector End View Reference: Entertainment/Communication Component Views 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Turn OFF the ignition.
  2. Disconnect the cellular microphone connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the cellular microphone signal 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 cellular microphone signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 9  Go to Step 6 
4 Test the drain wire circuit for an open. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 9  Go to Step 5 
5 Inspect for poor connections at the harness connector of the cellular microphone and harness connector of the vehicle communication interface module (VCIM). Refer to Testing for Intermittent Conditions and Poor Connections andConnector Repairs .
Did you find and correct the condition?		 - Go to Step 9  Go to Step 7 
6 Inspect for poor connections at the harness connector of the VCIM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 9  Go to Step 8 
7 Replace the cellular microphone. Refer to Mobile Telephone Microphone Replacement .
Did you complete the replacement?		 - Go to Step 9  -
8 Replace the VCIM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 9  -
9
  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
scientia non olet · About LEMON Manuals