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.
OnStar Microphone Malfunction
2001 Chevrolet Suburban C1500SECTION OnStar Microphone Malfunction
OnStar Microphone Malfunction
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: OnStar Schematics DEFINITION: The OnStar® call center operator can clearly be heard but will advise the caller that they cannot clearly hear them or cannot hear them at all. |
||||
| 1 | Did you perform the Cellular Communication Diagnostic System Check? | - | Go to Step 2 | Go to Diagnostic System Check - Cellular Communication |
| 2 |
|
- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 |
|
9 V | Go to Step 4 | Go to Step 5 |
| 4 | Measure the voltage from the Cellular Telephone Microphone Signal circuit to the drain wire. Does the voltage measure near the specified value? |
9 V | Go to Step 7 | Go to Step 6 |
| 5 | Test the Cellular Telephone Microphone Signal circuit for an open or a short to ground. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 14 | Go to Step 8 |
| 6 | Test the Drain Wire for an open. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 14 | Go to Step 11 |
| 7 | Test the drain wire circuit for a short to ground. Refer to Circuit Testing
, and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 14 | Go to Step 9 |
| 8 |
|
- | Go to Step 14 | Go to Step 9 |
| 9 | Test the microphone signal circuit between the VIU and VCU for an open or short to ground. Did you find and correct the condition? |
- | Go to Step 14 | Go to Step 10 |
| 10 | Inspect for poor connections at the harness connector of the Microphone assembly. 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 14 | Go to Step 13 |
| 11 | Inspect for poor connections at the harness connector of the VIU. 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 14 | Go to Step 12 |
| 12 | Replace the Microphone assembly. Refer to Mobile Telephone Microphone Replacement . Did you complete the replacement? |
- | Go to Step 14 | - |
| 13 |
IMPORTANT:
Replace the VIU. Refer to OnStar Vehicle Interface Unit Replacement .Did you complete the replacement?Perform the OnStar® setup procedure. |
Go to Step 14 | - | |
| 14 | Operate the system in order to verify the repair. Did you correct the condition? |
- | System OK | Go to Step 2 |
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.