Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G3500, VAN PASSENGER EXTENDEDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 8 (CELLULAR SYSTEM, ENTERTAINMENT SYSTEM, AND NAVIGATION SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESMICROPHONE INOPERATIVE - CALLER CANNOT BE HEARD
2008 Chevrolet Chevy Express G3500, Van Passenger Extended
Microphone Inoperative - Caller Cannot Be Heard
2008 Chevrolet Chevy Express G3500, Van Passenger ExtendedSECTION Microphone Inoperative - Caller Cannot Be Heard
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.
Microphone Inoperative - Caller Cannot Be Heard
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: OnStar Schematics Connector End View Reference: Entertainment/Communication Connector End Views DEFINITION: The OnStar® Call Center operator can clearly be heard but the operator is unable to hear the caller. |
||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | - | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 |
|
- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
| 3 |
|
9 V | Go to Step 4 | Go to Step 5 |
| 4 | Measure the voltage from the cellular microphone signal circuit to the drain wire circuit. Does the voltage measure greater than the specified value? |
9 V | Go to Step 7 | Go to Step 6 |
| 5 | Test the cellular microphone signal circuit for a short to ground. Refer to Circuit Testing
and Wiring Repairs
. Did you find and correct the condition? |
- | Go to Step 13 | Go to Step 8 |
| 6 | Test the drain wire 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 13 | Go to Step 9 |
| 7 | Test the drain wire for a short to ground. Did you find and correct the condition? |
- | Go to Step 13 | Go to Step 10 |
| 8 |
|
- | Go to Step 13 | Go to Step 9 |
| 9 | Inspect for poor connections at the harness connector of the cellular microphone. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
. Did you find and correct the condition? |
- | Go to Step 13 | Go to Step 12 |
| 10 | 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 13 | Go to Step 11 |
| 11 | Replace the cellular microphone. Refer to Mobile Telephone Microphone Replacement . Did you complete the replacement? |
- | Go to Step 13 | - |
| 12 | Replace the VCIM. Refer to Control Module References
for replacement, setup, and programming. 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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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.