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HOMESERVICE MANUALSISUZU2006ASCENDER S, 5.3 M, 4WDREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTENTERTAINMENT SYSTEMSCELLULAR COMMUNICATION SYSTEMSDIAGNOSTIC INFORMATION & PROCEDURESDTC B2455TEST DESCRIPTION
2006 Isuzu Ascender S, 5.3 M, 4WD

Test Description

2006 Isuzu Ascender S, 5.3 M, 4WDSECTION Test Description

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: 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 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 in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 9  Go to Step 6 
4 Test the cellular microphone low reference circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
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 in Wiring Systems.
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 in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 9  Go to Step 8 
7 Replace the cellular microphone. Refer to OnStar Microphone Replacement .
Did you complete the replacement?		 - Go to Step 9  -
8 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 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
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.